Disparities in prostate cancer in African American men: What primary care physicians can do

Article Type
Article
Changed
Mon, 10/02/2017 - 14:48
Display Headline
Disparities in prostate cancer in African American men: What primary care physicians can do
Author(s)
Ina Wu, MD
Charles S. Modlin, MD, MBA

Prostate cancer is the most common cancer affecting American men. In 2010, an estimated 217,730 men were diagnosed with it and 32,050 died of it.1 African American men are disproportionately affected, with a prostate cancer incidence two-thirds higher than whites and a mortality rate twice as high.1 Owing to such disparities, the life expectancy of African Americans is several years shorter than that of non-Hispanic whites.2

For the primary care provider, who is often the first access point for health care in the United States, it is important to understand what mechanisms may underlie these differences and what can be done to narrow the gap.3

WHAT IS THE CAUSE OF THESE DIFFERENCES?

Many studies have looked into the causes of the higher incidence of prostate cancer in African American men and their higher mortality rate from it. The disparity may be due to a variety of factors, some socioeconomic and some biologic.

Poorer access to care, or lower-quality care?

A study of US servicemen who had equal access to care showed that African American men had a higher rate of prostate cancer regardless of access to care and socioeconomic status.4

However, the 2002 Institute of Medicine report, Unequal Treatment: Confronting Racial and Ethnic Disparities in Health Care, found evidence that racial and ethnic minorities tend to receive lower-quality health care than whites, “even when access-related factors, such as patients’ insurance status and income, are controlled.”5

Genetic predisposition?

Some have proposed that the disparity may be a function of genetic predisposition.

Evidence of a genetic component to the high incidence and mortality rate in African American men comes from epidemiologic studies of men with similar genetic backgrounds. For example, men in Nigeria and Ghana also have a high incidence of prostate cancer, as do men of African descent in the Caribbean islands and in the United Kingdom.6

Chromosome 8q24 variants have been shown in several studies to be associated with prostate cancer risk and are more common in African American men.7–10 Some studies have also shown a higher rate of variations in cell apoptosis genes such as BCL211 and tumor-suppression genes such as EphB2 in African American men.12

These findings suggest that genetic differences may contribute to the higher prostate cancer incidence and mortality rate seen in African American men.

More-aggressive cancer, or later detection?

Not only do African American men tend to have a higher incidence of prostate cancer, they also tend to have more-aggressive disease (ie, a higher pathologic grade) at the time of diagnosis, which may contribute to the disparity in mortality rates.13–19

Initially, there was some controversy as to whether this observation is a result of genetic and biologic factors that may predispose African American men to more-aggressive disease, or if it is due to inadequate screening and delayed presentation. However, a body of evidence supports the contention that prostate cancer is more aggressive in African American men.

For example, a study of autopsy data from men who died of prostate cancer at ages 20 to 49 showed that the age of onset of prostate cancer was similar between African American and white men.20 The Surveillance Epidemiology and End Results (SEER) database showed that African American men had a higher incidence of metastatic disease across all age groups.20 A similar study conducted 10 years later confirmed that rates of subclinical prostate cancer in African American and white men do not differ by race at the early ages, but that advanced or metastatic disease occurred nearly four times as frequently in African American men.21

Another study examined prostate biopsies from African American men and found that their tumors expressed higher levels of biomarkers, suggesting they had more-aggressive disease.22

SCREENING FOR PROSTATE CANCER

Serum prostate-specific antigen (PSA) testing has become the method of choice for prostate cancer screening. However, PSA screening in asymptomatic men is under debate, because it can lead to overdetection and subsequent overtreatment of indolent disease.23

Several recent studies showed differing results from prostate cancer screening.

The US Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial found that the mortality rate was no lower with combined PSA screening and digital rectal examination during a median follow-up of 11 years than in a control group that had a lower rate of screening.24 However, further analysis of these data, with stratifying by comorbidities, showed that PSA screening in young and healthy men reduces the risk of death from prostate cancer, with minimal overtreatment.25

The European Randomized Study of Screening for Prostate Cancer found a statistically significant 20% reduction in deaths from prostate cancer with PSA screening, but that it was necessary to treat 48 men in order to save one life.26

Another study, published in 2010, showed that regular PSA screening reduced the rate of prostate cancer mortality by half over 14 years.27

African American men generally present with disease that is more advanced than in white men.28 This historically has been attributed to the fact that African Americans have been less likely to be screened for prostate cancer, though recent data indicate the gap is lessening.29–31 A cross-sectional study from the Texas Medical Center showed that 54.4% of African American men had received PSA screening, compared with 63.2% of white men.32

Another study showed that African Americans were more likely to have had a longer interval between PSA screenings before diagnosis, and that a longer PSA screening interval was associated with greater odds of having advanced disease at diagnosis.33 However, when the researchers controlled for the PSA screening interval, they found that African Americans had the same odds of being diagnosed with advanced prostate cancer as white patients did. They concluded that more frequent or systematic PSA screening may reduce the racial differences in cancer stage at diagnosis and in deaths.

 

 

Reasons for the disparities in screening

Many reasons have been proposed to explain why African Americans receive less screening, including poor communication between physicians and minority patients due to lack of cultural competency among physicians, lack of health insurance (and poor access to quality care as a result), and deficiency of knowledge about screening. Though awareness is rising, many African Americans are unaware of early detection methods for prostate cancer (eg, PSA testing), and other barriers such as cost and transportation exist that may prevent African American men from being screened.34,35

As gatekeepers, primary care physicians are in a position to address these shortcomings in patient education and to enhance the physician-patient relationship.36

Black men have higher PSA levels, with or without cancer

Physicians must also be aware of racial differences in PSA levels and realize that the predictive value of PSA in the diagnosis of prostate cancer may differ between African Americans and whites.

Black men, with or without prostate cancer, have been found to have higher PSA levels. Kyle and colleagues37 found that African American men without prostate cancer had significantly higher mean PSA levels than white men across all age groups. Furthermore, Vijayakumar et al38 found that African Americans with newly diagnosed localized prostate cancer had higher serum PSA levels than whites at diagnosis.

Although PSA cutoff levels have not been officially modified according to race, primary care physicians should have a lower threshold for referring African American men who have a suspiciously high PSA level for further urologic evaluation. Close partnership between the internist, family practitioner, and urologist will aid in the optimal use of PSA testing for the early detection of prostate cancer.

When to start PSA screening? How often to screen?

The age at which African American men should begin to have their PSA levels checked (with or without a digital rectal examination) continues to debated. However, the American Cancer Society39 recommends that African American men who have a father or brother who had prostate cancer before age 65 should begin having discussions with their physician on this topic and, with their informed consent, screening at age 45.

The frequency of PSA screening depends on the individual’s PSA level. The National Comprehensive Cancer Network40 recommends that men at high risk be offered a baseline PSA measurement and digital rectal examination at age 40 and, if the PSA level is higher than 1 ng/mL, that they be offered annual follow-ups. If the PSA level is less than 1 ng/mL, they recommend screening again at age 45. Risk factors for prostate cancer include family history as well as African American race.41

How should PSA levels be interpreted?

Interpreting PSA results is important in detecting prostate cancer at early stages.

At first, we believed the normal range of PSA for all men was 4.0 ng/mL or less. However, the American Urological Association now recognizes that the normal PSA range, in addition to varying along racial lines, also is age-dependent.42 The Cleveland Clinic Minority Men's Health Center's suggested normal ranges of PSA in African American men are:

  • Age 40–49: ≤ 2.5 ng/mL
  • Age 50–59: ≤ 3.0 ng/mL
  • Age 60–69: ≤ 3.5 ng/mL
  • Age 70–79: ≤ 4.5 ng/mL
  • Age > 80: ≤ 5.0 ng/mL.

Remember that an elevated PSA does not necessarily signify prostate cancer, and that these are reference ranges only and may vary in individual men.

SURVIVAL AFTER DIAGNOSIS

African American men with prostate cancer have significantly higher mortality rates than white men. The possible causes of worse outcomes are many, and there have been many studies that attempted to address this disparity. The question of a more biologically aggressive cancer was previously discussed, but additional factors such as socioeconomic factors, comorbidities, and treatment received have also been studied, and data are mixed.43–45

In a large SEER database review, once confounding variables of socioeconomic status, cancer stage, and treatment received were eliminated, African Americans had similar stage-for-stage survival from prostate cancer.46 Another study found, in 2,046 men, that differences in socioeconomic status explained the difference in mortality rates between white and black patients.47

However, other studies that adjusted for socioeconomic status as well as patient and tumor characteristics found that African American and Hispanic men were more likely to die of prostate cancer than white men.48

Do African American men receive less-aggressive care?

Studies have also determined that there may be differences in treatments offered to patients, which in turn negatively affect survival.28,49–53 Potentially curative local therapies (including radical surgery or radiation) may be recommended less often to black men because of major comorbidities or socioeconomic considerations.49–52

Additionally, potential metastatic disease may be identified in a less timely and accurate manner, as African American men are less likely to undergo pelvic lymph node dissection. This was associated with worse survival in men with poorly differentiated prostate cancer.53

However, returning to the possibility that prostate cancer is biologically more aggressive in African American men, some studies have shown that even after adjusting for treatment, African Americans continue to have worse survival rates.54,55 One study in men with stage T1 to T3 prostate cancer who chose brachytherapy for treatment reported that after adjusting for PSA, clinical stage, socioeconomic status, and comorbidities, African American and Hispanic race were associated with higher all-cause mortality rates.55

Equal care, equal outcomes?

In total, these results suggest that factors unrelated to tumor biology may be additional reasons for the poorer survival rates in African American men with prostate cancer. More favorable survival outcomes for African Americans with localized disease may be achieved with uniform assignment of treatment.

Fowler and Terrell56 reviewed the outcomes of 148 black and 209 white men with localized prostate cancer treated with surgery or radiation therapy over an 11-year period at a Veterans Administration hospital. Not surprisingly, the black men presented more often with advanced disease. However, survival outcomes were equivalent between whites and blacks when treatment was assigned in a uniform manner without regard to race. After a median follow-up of 96 months, there were no significant differences in all-cause, cause-specific, metastasis-free, clinical disease-free, or PSA recurrence-free survival rates in 109 black and 167 white men with low-stage cancer treated with surgery or radiation therapy or in 39 black and 42 white men with high-stage disease treated with radiotherapy.56

Similarly, Tewari et al57 studied a cohort of 402 African American and 642 white men, all of whom underwent radical prostatectomy for clinically localized prostate cancer. They were followed for PSA recurrence to determine if race-specific differences in PSA doubling time or histopathologic variables might account for the higher mortality rate in black men. While there were race-specific differences in baseline serum PSA and incidence of high-grade prostatic intraepithelial neoplasia, race was not an independent risk factor for biochemical recurrence. Instead, other variables such as the Gleason pathology score, bilateral cancers, and margin positivity were independently associated with biochemical recurrence.

Furthermore, researchers at Louisiana State University58 retrospectively analyzed data from 205 men of different races with early-stage prostate cancer. The African American men had a higher serum PSA level, suggesting more advanced disease or greater tumor burden at presentation, but no statistically significant differences were found among the pretreatment biopsy variables, including prostate volume (measured by ultrasonography), Gleason score, millimeters of cancer within the biopsy specimen, and percentage of cancer within the biopsy specimen. After treatment, there were no significant differences in survival outcomes along racial lines, leading the authors to conclude that early detection and treatment of prostate cancer in African Americans would be the best approach to lowering mortality rates.

Taken together, these data suggest that if localized prostate cancer is treated adequately and appropriately, African American patients may have improved survival rates.

 

 

DIETARY AND LIFESTYLE FACTORS

The incidence of prostate cancer is increasing in other countries where Western diets and lifestyles have been adopted,59,60 suggesting that nutritional factors may also contribute partly to prostate carcinogenesis. Culture- and race-specific differences in diet may play an important role in prostate cancer risk in certain racial minorities. Many aspects of diet and nutrition have been studied for their impact on prostate cancer.

Dietary risk factors

Too much red meat and processed meat? Although some have suggested that diets high in red and processed meats may lead to a higher risk of prostate cancer, a meta-analysis showed no association.61,62

Too much calcium? The European Prospective Investigation Into Cancer and Nutrition study found that high dietary intake of dairy protein and calcium from dairy products was associated with a higher risk of prostate cancer.63 A cohort study in the United States had similar findings with regard to calcium.64 However, the higher risk of prostate cancer was associated with consumption of 2,000 mg or more of calcium per day, which was consumed by only 2% of the study’s cohort and, as the study’s authors reported, fewer than 1% of US men. As such, only a small population of American men seem to be exposing themselves to a higher risk of prostate cancer by high calcium consumption.

High fat intake? Certain fatty acids have been implicated in general tumor genesis, and that risk has been extrapolated to prostate cancer.65 For example, high fat intake and obesity are associated with increased levels of insulin-like growth factor 1, which in turn has been shown to correlate with a significantly elevated risk of prostate cancer.63,65

Obesity has been shown to increase the risk of more-aggressive prostate cancer, but not of less-aggressive tumors.66 Moreover, men who lost weight had a lower risk of prostate cancer than those who maintained their weight over 10 years.66 Obesity may be particularly risky for African American men, in whom it was found to be associated with shorter biochemical relapse-free survival, whereas it was not an independent risk factor in white men.67

Preventive dietary agents have been elusive

Unfortunately, despite attempts to identify preventive dietary agents, none has yet been confirmed.

No benefit from selenium or vitamin E. The Selenium and Vitamin E Cancer Prevention Trial was discontinued, as there was no evidence that either agent prevented prostate cancer in relatively healthy men.68

Vitamin D? It has been suggested that lower levels of vitamin D could contribute to the higher rates of prostate cancer in African Americans, as vitamin D deficiency is more common in African Americans.69 However, several meta-analyses have shown no association between vitamin D and prostate cancer.70–72

Soy? Attempts at correlating the relatively low incidence of prostate cancer in Asians have revealed that high soy intake may be protective. Asians consume more soy than Americans do (100 vs 3 mg/day), and soy isoflavones such as genistein, glycitein, and daidzein lower the incidence of prostate cancer in laboratory mice.73

Other lifestyle factors

Other lifestyle factors have also been analyzed to see if they contribute to prostate cancer.

Pollution. Some studies have suggested that the etiology of prostate cancer may lie in environmental exposures to pesticides,74 metal industrial facilities,75 and urban living.76

Smoking. Watters et al77 found that current and former cigarette smokers were actually at a lower risk of being diagnosed with non-advanced prostate cancer, but current smokers were at higher risk of dying from prostate cancer.

Physical activity. A prospective study of lifetime physical activity of more than 45,000 men found that men who were not sedentary during work and who walked or bicycled more than 30 minutes per day during adult life had an approximately 20% lower incidence of prostate cancer.78

In sum, primary care providers who are generally promoting healthy lifestyles can point to a reduction in risk for prostate cancer as yet another benefit to a low-fat diet, a healthy body mass index, and daily exercise.

HOW PRIMARY CARE PHYSICIANS CAN HELP CLOSE THE GAP

Primary care physicians serve as the first point of health access for many in the United States today.

The diagnosis of prostate cancer is made more frequently in African American men than in other American men, often at a higher pathological grade, and with a worse mortality rate. Primary care physicians can help improve these statistics. Interventions targeting overall health, such as promotion of a healthy diet, could be established at primary care visits and could also reduce the incidence of prostate cancer in African American men. Patient education regarding prostate cancer screening, the impact of family history, and the rate of PSA screening could be improved.

Primary care physicians serve a vital role in health education and prostate cancer screening, and therefore they begin the process in potentially reducing the impact of prostate cancer in African American men. The racial disparity seen in prostate cancer may begin to be minimized with primary care physicians and specialists working together to ensure that all men receive appropriate treatment.

References
  1. Altekruse SF, Kosary CL, Krapcho M, et al. SEER Cancer Statistics Review, 1975–2007, National Cancer Institute. Bethesda, MD. http://seer.cancer.gov/csr/1975_2007/, based on November 2009 SEER data submission, posted to the SEER web site, 2010. Accessed April 2, 2011.
  2. Arias E. United States life tables, 2007. National vital statistics reports; vol 59 no 9. Hyattsville, MD: National Center for Health Statistics. 2011.
  3. Klein JB, Nguyen CT, Saffore L, Modlin C, Modlin CS. Racial disparities in urologic health care. J Natl Med Assoc 2010; 102:108–117.
  4. Wells TS, Bukowinski AT, Smith TC, et al. Racial differences in prostate cancer risk remain among US servicemen with equal access to care. Prostate 2010; 70:727–734.
  5. Smedley BD, Stith AY, Nelson AR, editors. Unequal Treatment: Confronting Racial and Ethnic Disparities in Health Care. Institute of Medicine. National Academy Press; 2002.
  6. Odedina FT, Akinremi TO, Chinegwundoh F, et al. Prostate cancer disparities in black men of African descent: a comparative literature review of prostate cancer burden among black men in the United States, Caribbean, United Kingdom, and West Africa. Infect Agent Cancer 2009; 4(suppl 1):S2.
  7. Okobia MN, Zmuda JM, Ferrell RE, Patrick AL, Bunker CH. Chromosome 8q24 variants are associated with prostate cancer risk in a high risk population of African ancestry. Prostate 2011; 71:1054–1063.
  8. Haiman CA, Chen GK, Blot WJ, et al. Characterizing genetic risk at known prostate cancer susceptibility loci in African Americans. PLoS Genet 2011; 7:e1001387.
  9. Freedman ML, Haiman CA, Patterson N, et al. Admixture mapping identifies 8q24 as a prostate cancer risk locus in African-American men. Proc Natl Acad Sci U S A 2006; 103:14068–14073.
  10. Chang BL, Isaacs SD, Wiley KE, et al. Genome-wide screen for prostate cancer susceptibility genes in men with clinically significant disease. Prostate 2005; 64:356–361.
  11. Hatcher D, Daniels G, Osman I, Lee P. Molecular mechanisms involving prostate cancer racial disparity. Am J Transl Res 2009; 1:235–248.
  12. Robbins CM, Hooker S, Kittles RA, Carpten JD. EphB2 SNPs and sporadic prostate cancer risk in African American men. PLoS One 2011; 6:e19494.
  13. American Cancer Society. Cancer Facts & Figures for African Americans 2009–2010. http://www.cancer.org/acs/groups/content/@nho/documents/document/cffaa20092010pdf.pdf. Accessed April 2, 2012.
  14. Ayanian JZ, Udvarhelyi IS, Gatsonis CA, Pashos CL, Epstein AM. Racial differences in the use of revascularization procedures after coronary angiography. JAMA 1993; 269:2642–2646.
  15. Fine MJ, Ibrahim SA, Thomas SB. The role of race and genetics in health disparities research. Am J Public Health 2005; 95:2125–2128.
  16. Horner RD, Oddone EZ, Matchar DB. Theories explaining racial differences in the utilization of diagnostic and therapeutic procedures for cerebrovascular disease. Milbank Q 1995; 73:443–462.
  17. Juckett G. Cross-cultural medicine. Am Fam Physician 2005; 72:2267–2274.
  18. Ndubuisi SC, Kofie VY, Andoh JY, Schwartz EM. Black-white differences in the stage at presentation of prostate cancer in the District of Columbia. Urology 1995; 46:71–77.
  19. Misra-Hebert AD. Physician cultural competence: cross-cultural communication improves care. Cleve Clin J Med 2003; 70:289,293,296–298.
  20. Powell I, Sakr W, Weiss L, et al. Prostate cancer is biologically more aggressive among African Americans than Caucasian men under age 70: hypothesis supported by autopsy and SEER data. Program and abstracts from the American Urological Association 95th Annual Meeting; April 29–May 4, 2000: Atlanta, GA.
  21. Powell IJ, Bock CH, Ruterbusch JJ, Sakr W. Evidence supports a faster growth rate and/or earlier transformation to clinically significant prostate cancer in black than in white American men, and influences racial progression and mortality disparity. J Urol 2010; 183:1792–1796.
  22. Kim HS, Moreira DM, Jayachandran J, et al. Prostate biopsies from black men express higher levels of aggressive disease biomarkers than prostate biopsies from white men. Prostate Cancer Prostatic Dis 2011; 14:262–265.
  23. Duffy MJ. Prostate-specific antigen: does the current evidence support its use in prostate cancer screening? Ann Clin Biochem 2011; 48:310–316.
  24. Andriole GL, Crawford ED, Grubb RL, et al; PLCO Project Team. Mortality results from a randomized prostate-cancer screening trial. N Engl J Med 2009; 360:1310–1319.
  25. Crawford ED, Grubb R, Black A, et al. Comorbidity and mortality results from a randomized prostate cancer screening trial. J Clin Oncol 2011; 29:355–361.
  26. Schröder FH, Hugosson J, Roobol MJ, et al; ERSPC Investigators. Screening and prostate-cancer mortality in a randomized European study. N Engl J Med 2009; 360:1320–1328.
  27. Hugosson J, Carlsson S, Aus G, et al. Mortality results from the Göteborg randomised population-based prostate-cancer screening trial. Lancet Oncol 2010; 11:725–732.
  28. Chornokur G, Dalton K, Borysova ME, Kumar NB. Disparities at presentation, diagnosis, treatment, and survival in African American men, affected by prostate cancer. Prostate 2011; 71:985–997.
  29. Boyd MD, Weinrich SP, Weinrich M, Norton A. Obstacles to prostate cancer screening in African-American men. J Natl Black Nurses Assoc 2001; 12:1–5.
  30. Freedland SJ, Isaacs WB. Explaining racial differences in prostate cancer in the United States: sociology or biology? Prostate 2005; 62:243–252.
  31. Ross LE, Berkowitz Z, Ekwueme DU. Use of the prostate-specific antigen test among U.S. men: findings from the 2005 National Health Interview Survey. Cancer Epidemiol Biomarkers Prev 2008; 17:636–644.
  32. Hosain GM, Sanderson M, Du XL, Chan W, Strom SS. Racial/ethnic differences in predictors of PSA screening in a tri-ethnic population. Cent Eur J Public Health 2011; 19:30–34.
  33. Carpenter WR, Howard DL, Taylor YJ, Ross LE, Wobker SE, Godley PA. Racial differences in PSA screening interval and stage at diagnosis. Cancer Causes Control 2010; 21:1071–1080.
  34. Betancourt JR, Maina AW. The Institute of Medicine report “Unequal Treatment”: implications for academic health centers. Mt Sinai J Med 2004; 71:314–321.
  35. Patel K, Kenerson D, Wang H, et al. Factors influencing prostate cancer screening in low-income African Americans in Tennessee. J Health Care Poor Underserved 2010; 21(suppl 1):114–126.
  36. Modlin CS. Culture, race, and disparities in health care. Cleve Clin J Med 2003; 70:283–288.
  37. Kyle C, Ewing T, Wu XC, et al. Statewide analysis of serum prostate specific antigen levels in Louisiana men without prostate cancer. J La State Med Soc 2004; 156:319–323.
  38. Vijayakumar S, Winter K, Sause W, et al. Prostate-specific antigen levels are higher in African-American than in white patients in a multicenter registration study: results of RTOG 94-12. Int J Radiat Oncol Biol Phys 1998; 40:17–25.
  39. Chang BL, Spangler E, Gallagher S, et al. Validation of genome-wide prostate cancer associations in men of African descent. Cancer Epidemiol Biomarkers Prev 2011; 20:23–32.
  40. National Comprehensive Cancer Network (NCCN). NCCN Stresses Importance of PSA Testing in High-Risk Men. http://www.nccn.org/about/news/newsinfo.asp?NewsID=218. Accessed April 2, 2012.
  41. National Cancer Institute. Prostate-Specific Antigen (PSA) Test. http://www.cancer.gov/cancertopics/factsheet/detection/PSA. Accessed April 2, 2012.
  42. Duggan D, Zheng SL, Knowlton M, et al. Two genome-wide association studies of aggressive prostate cancer implicate putative prostate tumor suppressor gene DAB2IP. Natl Cancer Inst 2007; 99:1836–1844.
  43. Grossfeld GD, Latini DM, Downs T, Lubeck DP, Mehta SS, Carroll PR. Is ethnicity an independent predictor of prostate cancer recurrence after radical prostatectomy? J Urol 2002; 168:2510–2515.
  44. Hoffman RM, Harlan LC, Klabunde CN, et al. Racial differences in initial treatment for clinically localized prostate cancer. Results from the prostate cancer outcomes study. J Gen Intern Med 2003; 18:845–853.
  45. Polednak AP. Prostate cancer treatment in black and white men: the need to consider both stage at diagnosis and socioeconomic status. J Natl Med Assoc 1998; 90:101–104.
  46. Merrill RM, Lyon JL. Explaining the difference in prostate cancer mortality rates between white and black men in the United States. Urology 2000; 55:730–735.
  47. Tewari AK, Gold HT, Demers RY, et al. Effect of socioeconomic factors on long-term mortality in men with clinically localized prostate cancer. Urology 2009; 73:624–630.
  48. White A, Coker AL, Du XL, Eggleston KS, Williams M. Racial/ethnic disparities in survival among men diagnosed with prostate cancer in Texas. Cancer 2011; 117:1080–1088.
  49. Moses KA, Paciorek AT, Penson DF, Carroll PR, Master VA. Impact of ethnicity on primary treatment choice and mortality in men with prostate cancer: data from CaPSURE. J Clin Oncol 2010; 28:1069–1074.
  50. Demers RY, Tiwari A, Wei J, Weiss LK, Severson RK, Montie J. Trends in the utilization of androgen-deprivation therapy for patients with prostate carcinoma suggest an effect on mortality. Cancer 2001; 92:2309–2317.
  51. Hsing AW, Chokkalingam AP. Prostate cancer epidemiology. Front Biosci 2006; 11:1388–1413.
  52. Schwartz K, Powell IJ, Underwood W, George J, Yee C, Banerjee M. Interplay of race, socioeconomic status, and treatment on survival of patients with prostate cancer. Urology 2009; 74:1296–1302.
  53. Hayn MH, Orom H, Shavers VL, et al. Racial/ethnic differences in receipt of pelvic lymph node dissection among men with localized/regional prostate cancer. Cancer 2011. [Epub ahead of print]
  54. Du XL, Lin CC, Johnson NJ, Altekruse S. Effects of individual-level socioeconomic factors on racial disparities in cancer treatment and survival: findings from the National Longitudinal Mortality Study, 1979–2003. Cancer 2011; 117:3242–3251.
  55. Winkfield KM, Chen MH, Dosoretz DE, et al. Race and survival following brachytherapy-based treatment for men with localized or locally advanced adenocarcinoma of the prostate. Int J Radiat Oncol Biol Phys 20115; 81:e345–e350.
  56. Fowler JE, Terrell F. Survival in blacks and whites after treatment for localized prostate cancer. J Urol 1996; 156:133–136.
  57. Tewari A, Horninger W, Badani KK, et al. Racial differences in serum prostate-specific antigen (PSA) doubling time, histopathological variables and long-term PSA recurrence between African-American and white American men undergoing radical prostatectomy for clinically localized prostate cancer. BJU Int 2005; 96:29–33.
  58. Bozeman C, Williams BJ, Whatley T, Crow A, Eastham J. Clinical and biopsy specimen features in black and white men with clinically localized prostate cancer. South Med J 2000; 93:400–402.
  59. Delongchamps NB, Singh A, Haas GP. Epidemiology of prostate cancer in Africa: another step in the understanding of the disease? Curr Probl Cancer 2007; 31:226–236.
  60. Quinn M, Babb P. Patterns and trends in prostate cancer incidence, survival, prevalence and mortality. Part I: international comparisons. BJU Int 2002; 90:162–173.
  61. Muller DC, Severi G, Baglietto L, et al. Dietary patterns and prostate cancer risk. Cancer Epidemiol Biomarkers Prev 2009; 18:3126–3129.
  62. Alexander DD, Mink PJ, Cushing CA, Sceurman B. A review and meta-analysis of prospective studies of red and processed meat intake and prostate cancer. Nutr J 2010; 9:50.
  63. Gonzalez CA, Riboli E. Diet and cancer prevention: contributions from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Eur J Cancer 2010; 46:2555–2562.
  64. Rodriguez C, McCullough ML, Mondul AM, et al. Calcium, dairy products, and risk of prostate cancer in a prospective cohort of United States men. Cancer Epidemiol Biomarkers Prev 2003; 12:597–603.
  65. McCarty MF. Mortality from Western cancers rose dramatically among African-Americans during the 20th century: are dietary animal products to blame? Med Hypotheses 2001; 57:169–174.
  66. Rodriguez C, Freedland SJ, Deka A, et al. Body mass index, weight change, and risk of prostate cancer in the Cancer Prevention Study II Nutrition Cohort. Cancer Epidemiol Biomarkers Prev 2007; 16:63–69.
  67. Spangler E, Zeigler-Johnson CM, Coomes M, Malkowicz SB, Wein A, Rebbeck TR. Association of obesity with tumor characteristics and treatment failure of prostate cancer in African-American and European American men. J Urol 2007; 178:1939–1944.
  68. Lippman SM, Klein EA, Goodman PJ, et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2009; 301:39–51.
  69. Oakley-Girvan I, Feldman D, Eccleshall TR, et al. Risk of early-onset prostate cancer in relation to germ line polymorphisms of the vitamin D receptor. Cancer Epidemiol Biomarkers Prev 2004; 13:1325–1330.
  70. Gilbert R, Martin RM, Beynon R, et al. Associations of circulating and dietary vitamin D with prostate cancer risk: a systematic review and dose-response meta-analysis. Cancer Causes Control 2011; 22:319–340.
  71. Gandini S, Boniol M, Haukka J, et al. Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. Int J Cancer 2011; 128:1414–1424.
  72. Yin L, Raum E, Haug U, Arndt V, Brenner H. Meta-analysis of longitudinal studies: serum vitamin D and prostate cancer risk. Cancer Epidemiol 2009; 33:435–445.
  73. McCormick DL, Johnson WD, Bosland MC, Lubet RA, Steele VE. Chemoprevention of rat prostate carcinogenesis by soy isoflavones and by Bowman-Birk inhibitor. Nutr Cancer 2007; 57:184–193.
  74. Belpomme D, Irigaray P, Ossondo M, Vacque D, Martin M. Prostate cancer as an environmental disease: an ecological study in the French Caribbean islands, Martinique and Guadeloupe. Int J Oncol 2009; 34:1037–1044.
  75. Ramis R, Diggle P, Cambra K, López-Abente G. Prostate cancer and industrial pollution. Risk around putative focus in a multi-source scenario. Environ Int 2011; 37:577–585.
  76. Dey S, Zhang Z, Hablas A, et al. Geographic patterns of cancer in the population-based registry of Egypt: possible links to environmental exposures. Cancer Epidemiol 2011; 35:254–264.
  77. Watters JL, Park Y, Hollenbeck A, Schatzkin A, Albanes D. Cigarette smoking and prostate cancer in a prospective US cohort study. Cancer Epidemiol Biomarkers Prev 2009; 18:2427–2435.
  78. Orsini N, Bellocco R, Bottai M, et al. A prospective study of lifetime physical activity and prostate cancer incidence and mortality. Br J Cancer 2009; 101:1932–1938.
Article PDF
media_c0192d0_313.pdf
Author and Disclosure Information

Ina Wu, MD
Glickman Urological and Kidney Institute, Cleveland Clinic

Charles S. Modlin, MD, MBA
Executive Director, Minority Health; Director, Minority Men’s Health Center; Staff, Glickman Urological and Kidney Institute, Cleveland Clinic; Associate Professor of Surgery, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Address: Charles S. Modlin, MD, MBA, Glickman Urological and Kidney Institute, Q10-1, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; e-mail modlinc@ccf.org

Issue
Cleveland Clinic Journal of Medicine - 79(5)
Publications
Cleveland Clinic Journal of Medicine
Topics
Oncology
Men's Health
Page Number
313-320
Sections
Addressing Disparities in Health Care
Author(s)
Ina Wu, MD
Charles S. Modlin, MD, MBA
Author(s)
Ina Wu, MD
Charles S. Modlin, MD, MBA
Author and Disclosure Information

Ina Wu, MD
Glickman Urological and Kidney Institute, Cleveland Clinic

Charles S. Modlin, MD, MBA
Executive Director, Minority Health; Director, Minority Men’s Health Center; Staff, Glickman Urological and Kidney Institute, Cleveland Clinic; Associate Professor of Surgery, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Address: Charles S. Modlin, MD, MBA, Glickman Urological and Kidney Institute, Q10-1, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; e-mail modlinc@ccf.org

Author and Disclosure Information

Ina Wu, MD
Glickman Urological and Kidney Institute, Cleveland Clinic

Charles S. Modlin, MD, MBA
Executive Director, Minority Health; Director, Minority Men’s Health Center; Staff, Glickman Urological and Kidney Institute, Cleveland Clinic; Associate Professor of Surgery, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Address: Charles S. Modlin, MD, MBA, Glickman Urological and Kidney Institute, Q10-1, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; e-mail modlinc@ccf.org

Article PDF
media_c0192d0_313.pdf
Article PDF
media_c0192d0_313.pdf

Prostate cancer is the most common cancer affecting American men. In 2010, an estimated 217,730 men were diagnosed with it and 32,050 died of it.1 African American men are disproportionately affected, with a prostate cancer incidence two-thirds higher than whites and a mortality rate twice as high.1 Owing to such disparities, the life expectancy of African Americans is several years shorter than that of non-Hispanic whites.2

For the primary care provider, who is often the first access point for health care in the United States, it is important to understand what mechanisms may underlie these differences and what can be done to narrow the gap.3

WHAT IS THE CAUSE OF THESE DIFFERENCES?

Many studies have looked into the causes of the higher incidence of prostate cancer in African American men and their higher mortality rate from it. The disparity may be due to a variety of factors, some socioeconomic and some biologic.

Poorer access to care, or lower-quality care?

A study of US servicemen who had equal access to care showed that African American men had a higher rate of prostate cancer regardless of access to care and socioeconomic status.4

However, the 2002 Institute of Medicine report, Unequal Treatment: Confronting Racial and Ethnic Disparities in Health Care, found evidence that racial and ethnic minorities tend to receive lower-quality health care than whites, “even when access-related factors, such as patients’ insurance status and income, are controlled.”5

Genetic predisposition?

Some have proposed that the disparity may be a function of genetic predisposition.

Evidence of a genetic component to the high incidence and mortality rate in African American men comes from epidemiologic studies of men with similar genetic backgrounds. For example, men in Nigeria and Ghana also have a high incidence of prostate cancer, as do men of African descent in the Caribbean islands and in the United Kingdom.6

Chromosome 8q24 variants have been shown in several studies to be associated with prostate cancer risk and are more common in African American men.7–10 Some studies have also shown a higher rate of variations in cell apoptosis genes such as BCL211 and tumor-suppression genes such as EphB2 in African American men.12

These findings suggest that genetic differences may contribute to the higher prostate cancer incidence and mortality rate seen in African American men.

More-aggressive cancer, or later detection?

Not only do African American men tend to have a higher incidence of prostate cancer, they also tend to have more-aggressive disease (ie, a higher pathologic grade) at the time of diagnosis, which may contribute to the disparity in mortality rates.13–19

Initially, there was some controversy as to whether this observation is a result of genetic and biologic factors that may predispose African American men to more-aggressive disease, or if it is due to inadequate screening and delayed presentation. However, a body of evidence supports the contention that prostate cancer is more aggressive in African American men.

For example, a study of autopsy data from men who died of prostate cancer at ages 20 to 49 showed that the age of onset of prostate cancer was similar between African American and white men.20 The Surveillance Epidemiology and End Results (SEER) database showed that African American men had a higher incidence of metastatic disease across all age groups.20 A similar study conducted 10 years later confirmed that rates of subclinical prostate cancer in African American and white men do not differ by race at the early ages, but that advanced or metastatic disease occurred nearly four times as frequently in African American men.21

Another study examined prostate biopsies from African American men and found that their tumors expressed higher levels of biomarkers, suggesting they had more-aggressive disease.22

SCREENING FOR PROSTATE CANCER

Serum prostate-specific antigen (PSA) testing has become the method of choice for prostate cancer screening. However, PSA screening in asymptomatic men is under debate, because it can lead to overdetection and subsequent overtreatment of indolent disease.23

Several recent studies showed differing results from prostate cancer screening.

The US Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial found that the mortality rate was no lower with combined PSA screening and digital rectal examination during a median follow-up of 11 years than in a control group that had a lower rate of screening.24 However, further analysis of these data, with stratifying by comorbidities, showed that PSA screening in young and healthy men reduces the risk of death from prostate cancer, with minimal overtreatment.25

The European Randomized Study of Screening for Prostate Cancer found a statistically significant 20% reduction in deaths from prostate cancer with PSA screening, but that it was necessary to treat 48 men in order to save one life.26

Another study, published in 2010, showed that regular PSA screening reduced the rate of prostate cancer mortality by half over 14 years.27

African American men generally present with disease that is more advanced than in white men.28 This historically has been attributed to the fact that African Americans have been less likely to be screened for prostate cancer, though recent data indicate the gap is lessening.29–31 A cross-sectional study from the Texas Medical Center showed that 54.4% of African American men had received PSA screening, compared with 63.2% of white men.32

Another study showed that African Americans were more likely to have had a longer interval between PSA screenings before diagnosis, and that a longer PSA screening interval was associated with greater odds of having advanced disease at diagnosis.33 However, when the researchers controlled for the PSA screening interval, they found that African Americans had the same odds of being diagnosed with advanced prostate cancer as white patients did. They concluded that more frequent or systematic PSA screening may reduce the racial differences in cancer stage at diagnosis and in deaths.

 

 

Reasons for the disparities in screening

Many reasons have been proposed to explain why African Americans receive less screening, including poor communication between physicians and minority patients due to lack of cultural competency among physicians, lack of health insurance (and poor access to quality care as a result), and deficiency of knowledge about screening. Though awareness is rising, many African Americans are unaware of early detection methods for prostate cancer (eg, PSA testing), and other barriers such as cost and transportation exist that may prevent African American men from being screened.34,35

As gatekeepers, primary care physicians are in a position to address these shortcomings in patient education and to enhance the physician-patient relationship.36

Black men have higher PSA levels, with or without cancer

Physicians must also be aware of racial differences in PSA levels and realize that the predictive value of PSA in the diagnosis of prostate cancer may differ between African Americans and whites.

Black men, with or without prostate cancer, have been found to have higher PSA levels. Kyle and colleagues37 found that African American men without prostate cancer had significantly higher mean PSA levels than white men across all age groups. Furthermore, Vijayakumar et al38 found that African Americans with newly diagnosed localized prostate cancer had higher serum PSA levels than whites at diagnosis.

Although PSA cutoff levels have not been officially modified according to race, primary care physicians should have a lower threshold for referring African American men who have a suspiciously high PSA level for further urologic evaluation. Close partnership between the internist, family practitioner, and urologist will aid in the optimal use of PSA testing for the early detection of prostate cancer.

When to start PSA screening? How often to screen?

The age at which African American men should begin to have their PSA levels checked (with or without a digital rectal examination) continues to debated. However, the American Cancer Society39 recommends that African American men who have a father or brother who had prostate cancer before age 65 should begin having discussions with their physician on this topic and, with their informed consent, screening at age 45.

The frequency of PSA screening depends on the individual’s PSA level. The National Comprehensive Cancer Network40 recommends that men at high risk be offered a baseline PSA measurement and digital rectal examination at age 40 and, if the PSA level is higher than 1 ng/mL, that they be offered annual follow-ups. If the PSA level is less than 1 ng/mL, they recommend screening again at age 45. Risk factors for prostate cancer include family history as well as African American race.41

How should PSA levels be interpreted?

Interpreting PSA results is important in detecting prostate cancer at early stages.

At first, we believed the normal range of PSA for all men was 4.0 ng/mL or less. However, the American Urological Association now recognizes that the normal PSA range, in addition to varying along racial lines, also is age-dependent.42 The Cleveland Clinic Minority Men's Health Center's suggested normal ranges of PSA in African American men are:

  • Age 40–49: ≤ 2.5 ng/mL
  • Age 50–59: ≤ 3.0 ng/mL
  • Age 60–69: ≤ 3.5 ng/mL
  • Age 70–79: ≤ 4.5 ng/mL
  • Age > 80: ≤ 5.0 ng/mL.

Remember that an elevated PSA does not necessarily signify prostate cancer, and that these are reference ranges only and may vary in individual men.

SURVIVAL AFTER DIAGNOSIS

African American men with prostate cancer have significantly higher mortality rates than white men. The possible causes of worse outcomes are many, and there have been many studies that attempted to address this disparity. The question of a more biologically aggressive cancer was previously discussed, but additional factors such as socioeconomic factors, comorbidities, and treatment received have also been studied, and data are mixed.43–45

In a large SEER database review, once confounding variables of socioeconomic status, cancer stage, and treatment received were eliminated, African Americans had similar stage-for-stage survival from prostate cancer.46 Another study found, in 2,046 men, that differences in socioeconomic status explained the difference in mortality rates between white and black patients.47

However, other studies that adjusted for socioeconomic status as well as patient and tumor characteristics found that African American and Hispanic men were more likely to die of prostate cancer than white men.48

Do African American men receive less-aggressive care?

Studies have also determined that there may be differences in treatments offered to patients, which in turn negatively affect survival.28,49–53 Potentially curative local therapies (including radical surgery or radiation) may be recommended less often to black men because of major comorbidities or socioeconomic considerations.49–52

Additionally, potential metastatic disease may be identified in a less timely and accurate manner, as African American men are less likely to undergo pelvic lymph node dissection. This was associated with worse survival in men with poorly differentiated prostate cancer.53

However, returning to the possibility that prostate cancer is biologically more aggressive in African American men, some studies have shown that even after adjusting for treatment, African Americans continue to have worse survival rates.54,55 One study in men with stage T1 to T3 prostate cancer who chose brachytherapy for treatment reported that after adjusting for PSA, clinical stage, socioeconomic status, and comorbidities, African American and Hispanic race were associated with higher all-cause mortality rates.55

Equal care, equal outcomes?

In total, these results suggest that factors unrelated to tumor biology may be additional reasons for the poorer survival rates in African American men with prostate cancer. More favorable survival outcomes for African Americans with localized disease may be achieved with uniform assignment of treatment.

Fowler and Terrell56 reviewed the outcomes of 148 black and 209 white men with localized prostate cancer treated with surgery or radiation therapy over an 11-year period at a Veterans Administration hospital. Not surprisingly, the black men presented more often with advanced disease. However, survival outcomes were equivalent between whites and blacks when treatment was assigned in a uniform manner without regard to race. After a median follow-up of 96 months, there were no significant differences in all-cause, cause-specific, metastasis-free, clinical disease-free, or PSA recurrence-free survival rates in 109 black and 167 white men with low-stage cancer treated with surgery or radiation therapy or in 39 black and 42 white men with high-stage disease treated with radiotherapy.56

Similarly, Tewari et al57 studied a cohort of 402 African American and 642 white men, all of whom underwent radical prostatectomy for clinically localized prostate cancer. They were followed for PSA recurrence to determine if race-specific differences in PSA doubling time or histopathologic variables might account for the higher mortality rate in black men. While there were race-specific differences in baseline serum PSA and incidence of high-grade prostatic intraepithelial neoplasia, race was not an independent risk factor for biochemical recurrence. Instead, other variables such as the Gleason pathology score, bilateral cancers, and margin positivity were independently associated with biochemical recurrence.

Furthermore, researchers at Louisiana State University58 retrospectively analyzed data from 205 men of different races with early-stage prostate cancer. The African American men had a higher serum PSA level, suggesting more advanced disease or greater tumor burden at presentation, but no statistically significant differences were found among the pretreatment biopsy variables, including prostate volume (measured by ultrasonography), Gleason score, millimeters of cancer within the biopsy specimen, and percentage of cancer within the biopsy specimen. After treatment, there were no significant differences in survival outcomes along racial lines, leading the authors to conclude that early detection and treatment of prostate cancer in African Americans would be the best approach to lowering mortality rates.

Taken together, these data suggest that if localized prostate cancer is treated adequately and appropriately, African American patients may have improved survival rates.

 

 

DIETARY AND LIFESTYLE FACTORS

The incidence of prostate cancer is increasing in other countries where Western diets and lifestyles have been adopted,59,60 suggesting that nutritional factors may also contribute partly to prostate carcinogenesis. Culture- and race-specific differences in diet may play an important role in prostate cancer risk in certain racial minorities. Many aspects of diet and nutrition have been studied for their impact on prostate cancer.

Dietary risk factors

Too much red meat and processed meat? Although some have suggested that diets high in red and processed meats may lead to a higher risk of prostate cancer, a meta-analysis showed no association.61,62

Too much calcium? The European Prospective Investigation Into Cancer and Nutrition study found that high dietary intake of dairy protein and calcium from dairy products was associated with a higher risk of prostate cancer.63 A cohort study in the United States had similar findings with regard to calcium.64 However, the higher risk of prostate cancer was associated with consumption of 2,000 mg or more of calcium per day, which was consumed by only 2% of the study’s cohort and, as the study’s authors reported, fewer than 1% of US men. As such, only a small population of American men seem to be exposing themselves to a higher risk of prostate cancer by high calcium consumption.

High fat intake? Certain fatty acids have been implicated in general tumor genesis, and that risk has been extrapolated to prostate cancer.65 For example, high fat intake and obesity are associated with increased levels of insulin-like growth factor 1, which in turn has been shown to correlate with a significantly elevated risk of prostate cancer.63,65

Obesity has been shown to increase the risk of more-aggressive prostate cancer, but not of less-aggressive tumors.66 Moreover, men who lost weight had a lower risk of prostate cancer than those who maintained their weight over 10 years.66 Obesity may be particularly risky for African American men, in whom it was found to be associated with shorter biochemical relapse-free survival, whereas it was not an independent risk factor in white men.67

Preventive dietary agents have been elusive

Unfortunately, despite attempts to identify preventive dietary agents, none has yet been confirmed.

No benefit from selenium or vitamin E. The Selenium and Vitamin E Cancer Prevention Trial was discontinued, as there was no evidence that either agent prevented prostate cancer in relatively healthy men.68

Vitamin D? It has been suggested that lower levels of vitamin D could contribute to the higher rates of prostate cancer in African Americans, as vitamin D deficiency is more common in African Americans.69 However, several meta-analyses have shown no association between vitamin D and prostate cancer.70–72

Soy? Attempts at correlating the relatively low incidence of prostate cancer in Asians have revealed that high soy intake may be protective. Asians consume more soy than Americans do (100 vs 3 mg/day), and soy isoflavones such as genistein, glycitein, and daidzein lower the incidence of prostate cancer in laboratory mice.73

Other lifestyle factors

Other lifestyle factors have also been analyzed to see if they contribute to prostate cancer.

Pollution. Some studies have suggested that the etiology of prostate cancer may lie in environmental exposures to pesticides,74 metal industrial facilities,75 and urban living.76

Smoking. Watters et al77 found that current and former cigarette smokers were actually at a lower risk of being diagnosed with non-advanced prostate cancer, but current smokers were at higher risk of dying from prostate cancer.

Physical activity. A prospective study of lifetime physical activity of more than 45,000 men found that men who were not sedentary during work and who walked or bicycled more than 30 minutes per day during adult life had an approximately 20% lower incidence of prostate cancer.78

In sum, primary care providers who are generally promoting healthy lifestyles can point to a reduction in risk for prostate cancer as yet another benefit to a low-fat diet, a healthy body mass index, and daily exercise.

HOW PRIMARY CARE PHYSICIANS CAN HELP CLOSE THE GAP

Primary care physicians serve as the first point of health access for many in the United States today.

The diagnosis of prostate cancer is made more frequently in African American men than in other American men, often at a higher pathological grade, and with a worse mortality rate. Primary care physicians can help improve these statistics. Interventions targeting overall health, such as promotion of a healthy diet, could be established at primary care visits and could also reduce the incidence of prostate cancer in African American men. Patient education regarding prostate cancer screening, the impact of family history, and the rate of PSA screening could be improved.

Primary care physicians serve a vital role in health education and prostate cancer screening, and therefore they begin the process in potentially reducing the impact of prostate cancer in African American men. The racial disparity seen in prostate cancer may begin to be minimized with primary care physicians and specialists working together to ensure that all men receive appropriate treatment.

Prostate cancer is the most common cancer affecting American men. In 2010, an estimated 217,730 men were diagnosed with it and 32,050 died of it.1 African American men are disproportionately affected, with a prostate cancer incidence two-thirds higher than whites and a mortality rate twice as high.1 Owing to such disparities, the life expectancy of African Americans is several years shorter than that of non-Hispanic whites.2

For the primary care provider, who is often the first access point for health care in the United States, it is important to understand what mechanisms may underlie these differences and what can be done to narrow the gap.3

WHAT IS THE CAUSE OF THESE DIFFERENCES?

Many studies have looked into the causes of the higher incidence of prostate cancer in African American men and their higher mortality rate from it. The disparity may be due to a variety of factors, some socioeconomic and some biologic.

Poorer access to care, or lower-quality care?

A study of US servicemen who had equal access to care showed that African American men had a higher rate of prostate cancer regardless of access to care and socioeconomic status.4

However, the 2002 Institute of Medicine report, Unequal Treatment: Confronting Racial and Ethnic Disparities in Health Care, found evidence that racial and ethnic minorities tend to receive lower-quality health care than whites, “even when access-related factors, such as patients’ insurance status and income, are controlled.”5

Genetic predisposition?

Some have proposed that the disparity may be a function of genetic predisposition.

Evidence of a genetic component to the high incidence and mortality rate in African American men comes from epidemiologic studies of men with similar genetic backgrounds. For example, men in Nigeria and Ghana also have a high incidence of prostate cancer, as do men of African descent in the Caribbean islands and in the United Kingdom.6

Chromosome 8q24 variants have been shown in several studies to be associated with prostate cancer risk and are more common in African American men.7–10 Some studies have also shown a higher rate of variations in cell apoptosis genes such as BCL211 and tumor-suppression genes such as EphB2 in African American men.12

These findings suggest that genetic differences may contribute to the higher prostate cancer incidence and mortality rate seen in African American men.

More-aggressive cancer, or later detection?

Not only do African American men tend to have a higher incidence of prostate cancer, they also tend to have more-aggressive disease (ie, a higher pathologic grade) at the time of diagnosis, which may contribute to the disparity in mortality rates.13–19

Initially, there was some controversy as to whether this observation is a result of genetic and biologic factors that may predispose African American men to more-aggressive disease, or if it is due to inadequate screening and delayed presentation. However, a body of evidence supports the contention that prostate cancer is more aggressive in African American men.

For example, a study of autopsy data from men who died of prostate cancer at ages 20 to 49 showed that the age of onset of prostate cancer was similar between African American and white men.20 The Surveillance Epidemiology and End Results (SEER) database showed that African American men had a higher incidence of metastatic disease across all age groups.20 A similar study conducted 10 years later confirmed that rates of subclinical prostate cancer in African American and white men do not differ by race at the early ages, but that advanced or metastatic disease occurred nearly four times as frequently in African American men.21

Another study examined prostate biopsies from African American men and found that their tumors expressed higher levels of biomarkers, suggesting they had more-aggressive disease.22

SCREENING FOR PROSTATE CANCER

Serum prostate-specific antigen (PSA) testing has become the method of choice for prostate cancer screening. However, PSA screening in asymptomatic men is under debate, because it can lead to overdetection and subsequent overtreatment of indolent disease.23

Several recent studies showed differing results from prostate cancer screening.

The US Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial found that the mortality rate was no lower with combined PSA screening and digital rectal examination during a median follow-up of 11 years than in a control group that had a lower rate of screening.24 However, further analysis of these data, with stratifying by comorbidities, showed that PSA screening in young and healthy men reduces the risk of death from prostate cancer, with minimal overtreatment.25

The European Randomized Study of Screening for Prostate Cancer found a statistically significant 20% reduction in deaths from prostate cancer with PSA screening, but that it was necessary to treat 48 men in order to save one life.26

Another study, published in 2010, showed that regular PSA screening reduced the rate of prostate cancer mortality by half over 14 years.27

African American men generally present with disease that is more advanced than in white men.28 This historically has been attributed to the fact that African Americans have been less likely to be screened for prostate cancer, though recent data indicate the gap is lessening.29–31 A cross-sectional study from the Texas Medical Center showed that 54.4% of African American men had received PSA screening, compared with 63.2% of white men.32

Another study showed that African Americans were more likely to have had a longer interval between PSA screenings before diagnosis, and that a longer PSA screening interval was associated with greater odds of having advanced disease at diagnosis.33 However, when the researchers controlled for the PSA screening interval, they found that African Americans had the same odds of being diagnosed with advanced prostate cancer as white patients did. They concluded that more frequent or systematic PSA screening may reduce the racial differences in cancer stage at diagnosis and in deaths.

 

 

Reasons for the disparities in screening

Many reasons have been proposed to explain why African Americans receive less screening, including poor communication between physicians and minority patients due to lack of cultural competency among physicians, lack of health insurance (and poor access to quality care as a result), and deficiency of knowledge about screening. Though awareness is rising, many African Americans are unaware of early detection methods for prostate cancer (eg, PSA testing), and other barriers such as cost and transportation exist that may prevent African American men from being screened.34,35

As gatekeepers, primary care physicians are in a position to address these shortcomings in patient education and to enhance the physician-patient relationship.36

Black men have higher PSA levels, with or without cancer

Physicians must also be aware of racial differences in PSA levels and realize that the predictive value of PSA in the diagnosis of prostate cancer may differ between African Americans and whites.

Black men, with or without prostate cancer, have been found to have higher PSA levels. Kyle and colleagues37 found that African American men without prostate cancer had significantly higher mean PSA levels than white men across all age groups. Furthermore, Vijayakumar et al38 found that African Americans with newly diagnosed localized prostate cancer had higher serum PSA levels than whites at diagnosis.

Although PSA cutoff levels have not been officially modified according to race, primary care physicians should have a lower threshold for referring African American men who have a suspiciously high PSA level for further urologic evaluation. Close partnership between the internist, family practitioner, and urologist will aid in the optimal use of PSA testing for the early detection of prostate cancer.

When to start PSA screening? How often to screen?

The age at which African American men should begin to have their PSA levels checked (with or without a digital rectal examination) continues to debated. However, the American Cancer Society39 recommends that African American men who have a father or brother who had prostate cancer before age 65 should begin having discussions with their physician on this topic and, with their informed consent, screening at age 45.

The frequency of PSA screening depends on the individual’s PSA level. The National Comprehensive Cancer Network40 recommends that men at high risk be offered a baseline PSA measurement and digital rectal examination at age 40 and, if the PSA level is higher than 1 ng/mL, that they be offered annual follow-ups. If the PSA level is less than 1 ng/mL, they recommend screening again at age 45. Risk factors for prostate cancer include family history as well as African American race.41

How should PSA levels be interpreted?

Interpreting PSA results is important in detecting prostate cancer at early stages.

At first, we believed the normal range of PSA for all men was 4.0 ng/mL or less. However, the American Urological Association now recognizes that the normal PSA range, in addition to varying along racial lines, also is age-dependent.42 The Cleveland Clinic Minority Men's Health Center's suggested normal ranges of PSA in African American men are:

  • Age 40–49: ≤ 2.5 ng/mL
  • Age 50–59: ≤ 3.0 ng/mL
  • Age 60–69: ≤ 3.5 ng/mL
  • Age 70–79: ≤ 4.5 ng/mL
  • Age > 80: ≤ 5.0 ng/mL.

Remember that an elevated PSA does not necessarily signify prostate cancer, and that these are reference ranges only and may vary in individual men.

SURVIVAL AFTER DIAGNOSIS

African American men with prostate cancer have significantly higher mortality rates than white men. The possible causes of worse outcomes are many, and there have been many studies that attempted to address this disparity. The question of a more biologically aggressive cancer was previously discussed, but additional factors such as socioeconomic factors, comorbidities, and treatment received have also been studied, and data are mixed.43–45

In a large SEER database review, once confounding variables of socioeconomic status, cancer stage, and treatment received were eliminated, African Americans had similar stage-for-stage survival from prostate cancer.46 Another study found, in 2,046 men, that differences in socioeconomic status explained the difference in mortality rates between white and black patients.47

However, other studies that adjusted for socioeconomic status as well as patient and tumor characteristics found that African American and Hispanic men were more likely to die of prostate cancer than white men.48

Do African American men receive less-aggressive care?

Studies have also determined that there may be differences in treatments offered to patients, which in turn negatively affect survival.28,49–53 Potentially curative local therapies (including radical surgery or radiation) may be recommended less often to black men because of major comorbidities or socioeconomic considerations.49–52

Additionally, potential metastatic disease may be identified in a less timely and accurate manner, as African American men are less likely to undergo pelvic lymph node dissection. This was associated with worse survival in men with poorly differentiated prostate cancer.53

However, returning to the possibility that prostate cancer is biologically more aggressive in African American men, some studies have shown that even after adjusting for treatment, African Americans continue to have worse survival rates.54,55 One study in men with stage T1 to T3 prostate cancer who chose brachytherapy for treatment reported that after adjusting for PSA, clinical stage, socioeconomic status, and comorbidities, African American and Hispanic race were associated with higher all-cause mortality rates.55

Equal care, equal outcomes?

In total, these results suggest that factors unrelated to tumor biology may be additional reasons for the poorer survival rates in African American men with prostate cancer. More favorable survival outcomes for African Americans with localized disease may be achieved with uniform assignment of treatment.

Fowler and Terrell56 reviewed the outcomes of 148 black and 209 white men with localized prostate cancer treated with surgery or radiation therapy over an 11-year period at a Veterans Administration hospital. Not surprisingly, the black men presented more often with advanced disease. However, survival outcomes were equivalent between whites and blacks when treatment was assigned in a uniform manner without regard to race. After a median follow-up of 96 months, there were no significant differences in all-cause, cause-specific, metastasis-free, clinical disease-free, or PSA recurrence-free survival rates in 109 black and 167 white men with low-stage cancer treated with surgery or radiation therapy or in 39 black and 42 white men with high-stage disease treated with radiotherapy.56

Similarly, Tewari et al57 studied a cohort of 402 African American and 642 white men, all of whom underwent radical prostatectomy for clinically localized prostate cancer. They were followed for PSA recurrence to determine if race-specific differences in PSA doubling time or histopathologic variables might account for the higher mortality rate in black men. While there were race-specific differences in baseline serum PSA and incidence of high-grade prostatic intraepithelial neoplasia, race was not an independent risk factor for biochemical recurrence. Instead, other variables such as the Gleason pathology score, bilateral cancers, and margin positivity were independently associated with biochemical recurrence.

Furthermore, researchers at Louisiana State University58 retrospectively analyzed data from 205 men of different races with early-stage prostate cancer. The African American men had a higher serum PSA level, suggesting more advanced disease or greater tumor burden at presentation, but no statistically significant differences were found among the pretreatment biopsy variables, including prostate volume (measured by ultrasonography), Gleason score, millimeters of cancer within the biopsy specimen, and percentage of cancer within the biopsy specimen. After treatment, there were no significant differences in survival outcomes along racial lines, leading the authors to conclude that early detection and treatment of prostate cancer in African Americans would be the best approach to lowering mortality rates.

Taken together, these data suggest that if localized prostate cancer is treated adequately and appropriately, African American patients may have improved survival rates.

 

 

DIETARY AND LIFESTYLE FACTORS

The incidence of prostate cancer is increasing in other countries where Western diets and lifestyles have been adopted,59,60 suggesting that nutritional factors may also contribute partly to prostate carcinogenesis. Culture- and race-specific differences in diet may play an important role in prostate cancer risk in certain racial minorities. Many aspects of diet and nutrition have been studied for their impact on prostate cancer.

Dietary risk factors

Too much red meat and processed meat? Although some have suggested that diets high in red and processed meats may lead to a higher risk of prostate cancer, a meta-analysis showed no association.61,62

Too much calcium? The European Prospective Investigation Into Cancer and Nutrition study found that high dietary intake of dairy protein and calcium from dairy products was associated with a higher risk of prostate cancer.63 A cohort study in the United States had similar findings with regard to calcium.64 However, the higher risk of prostate cancer was associated with consumption of 2,000 mg or more of calcium per day, which was consumed by only 2% of the study’s cohort and, as the study’s authors reported, fewer than 1% of US men. As such, only a small population of American men seem to be exposing themselves to a higher risk of prostate cancer by high calcium consumption.

High fat intake? Certain fatty acids have been implicated in general tumor genesis, and that risk has been extrapolated to prostate cancer.65 For example, high fat intake and obesity are associated with increased levels of insulin-like growth factor 1, which in turn has been shown to correlate with a significantly elevated risk of prostate cancer.63,65

Obesity has been shown to increase the risk of more-aggressive prostate cancer, but not of less-aggressive tumors.66 Moreover, men who lost weight had a lower risk of prostate cancer than those who maintained their weight over 10 years.66 Obesity may be particularly risky for African American men, in whom it was found to be associated with shorter biochemical relapse-free survival, whereas it was not an independent risk factor in white men.67

Preventive dietary agents have been elusive

Unfortunately, despite attempts to identify preventive dietary agents, none has yet been confirmed.

No benefit from selenium or vitamin E. The Selenium and Vitamin E Cancer Prevention Trial was discontinued, as there was no evidence that either agent prevented prostate cancer in relatively healthy men.68

Vitamin D? It has been suggested that lower levels of vitamin D could contribute to the higher rates of prostate cancer in African Americans, as vitamin D deficiency is more common in African Americans.69 However, several meta-analyses have shown no association between vitamin D and prostate cancer.70–72

Soy? Attempts at correlating the relatively low incidence of prostate cancer in Asians have revealed that high soy intake may be protective. Asians consume more soy than Americans do (100 vs 3 mg/day), and soy isoflavones such as genistein, glycitein, and daidzein lower the incidence of prostate cancer in laboratory mice.73

Other lifestyle factors

Other lifestyle factors have also been analyzed to see if they contribute to prostate cancer.

Pollution. Some studies have suggested that the etiology of prostate cancer may lie in environmental exposures to pesticides,74 metal industrial facilities,75 and urban living.76

Smoking. Watters et al77 found that current and former cigarette smokers were actually at a lower risk of being diagnosed with non-advanced prostate cancer, but current smokers were at higher risk of dying from prostate cancer.

Physical activity. A prospective study of lifetime physical activity of more than 45,000 men found that men who were not sedentary during work and who walked or bicycled more than 30 minutes per day during adult life had an approximately 20% lower incidence of prostate cancer.78

In sum, primary care providers who are generally promoting healthy lifestyles can point to a reduction in risk for prostate cancer as yet another benefit to a low-fat diet, a healthy body mass index, and daily exercise.

HOW PRIMARY CARE PHYSICIANS CAN HELP CLOSE THE GAP

Primary care physicians serve as the first point of health access for many in the United States today.

The diagnosis of prostate cancer is made more frequently in African American men than in other American men, often at a higher pathological grade, and with a worse mortality rate. Primary care physicians can help improve these statistics. Interventions targeting overall health, such as promotion of a healthy diet, could be established at primary care visits and could also reduce the incidence of prostate cancer in African American men. Patient education regarding prostate cancer screening, the impact of family history, and the rate of PSA screening could be improved.

Primary care physicians serve a vital role in health education and prostate cancer screening, and therefore they begin the process in potentially reducing the impact of prostate cancer in African American men. The racial disparity seen in prostate cancer may begin to be minimized with primary care physicians and specialists working together to ensure that all men receive appropriate treatment.

References
  1. Altekruse SF, Kosary CL, Krapcho M, et al. SEER Cancer Statistics Review, 1975–2007, National Cancer Institute. Bethesda, MD. http://seer.cancer.gov/csr/1975_2007/, based on November 2009 SEER data submission, posted to the SEER web site, 2010. Accessed April 2, 2011.
  2. Arias E. United States life tables, 2007. National vital statistics reports; vol 59 no 9. Hyattsville, MD: National Center for Health Statistics. 2011.
  3. Klein JB, Nguyen CT, Saffore L, Modlin C, Modlin CS. Racial disparities in urologic health care. J Natl Med Assoc 2010; 102:108–117.
  4. Wells TS, Bukowinski AT, Smith TC, et al. Racial differences in prostate cancer risk remain among US servicemen with equal access to care. Prostate 2010; 70:727–734.
  5. Smedley BD, Stith AY, Nelson AR, editors. Unequal Treatment: Confronting Racial and Ethnic Disparities in Health Care. Institute of Medicine. National Academy Press; 2002.
  6. Odedina FT, Akinremi TO, Chinegwundoh F, et al. Prostate cancer disparities in black men of African descent: a comparative literature review of prostate cancer burden among black men in the United States, Caribbean, United Kingdom, and West Africa. Infect Agent Cancer 2009; 4(suppl 1):S2.
  7. Okobia MN, Zmuda JM, Ferrell RE, Patrick AL, Bunker CH. Chromosome 8q24 variants are associated with prostate cancer risk in a high risk population of African ancestry. Prostate 2011; 71:1054–1063.
  8. Haiman CA, Chen GK, Blot WJ, et al. Characterizing genetic risk at known prostate cancer susceptibility loci in African Americans. PLoS Genet 2011; 7:e1001387.
  9. Freedman ML, Haiman CA, Patterson N, et al. Admixture mapping identifies 8q24 as a prostate cancer risk locus in African-American men. Proc Natl Acad Sci U S A 2006; 103:14068–14073.
  10. Chang BL, Isaacs SD, Wiley KE, et al. Genome-wide screen for prostate cancer susceptibility genes in men with clinically significant disease. Prostate 2005; 64:356–361.
  11. Hatcher D, Daniels G, Osman I, Lee P. Molecular mechanisms involving prostate cancer racial disparity. Am J Transl Res 2009; 1:235–248.
  12. Robbins CM, Hooker S, Kittles RA, Carpten JD. EphB2 SNPs and sporadic prostate cancer risk in African American men. PLoS One 2011; 6:e19494.
  13. American Cancer Society. Cancer Facts & Figures for African Americans 2009–2010. http://www.cancer.org/acs/groups/content/@nho/documents/document/cffaa20092010pdf.pdf. Accessed April 2, 2012.
  14. Ayanian JZ, Udvarhelyi IS, Gatsonis CA, Pashos CL, Epstein AM. Racial differences in the use of revascularization procedures after coronary angiography. JAMA 1993; 269:2642–2646.
  15. Fine MJ, Ibrahim SA, Thomas SB. The role of race and genetics in health disparities research. Am J Public Health 2005; 95:2125–2128.
  16. Horner RD, Oddone EZ, Matchar DB. Theories explaining racial differences in the utilization of diagnostic and therapeutic procedures for cerebrovascular disease. Milbank Q 1995; 73:443–462.
  17. Juckett G. Cross-cultural medicine. Am Fam Physician 2005; 72:2267–2274.
  18. Ndubuisi SC, Kofie VY, Andoh JY, Schwartz EM. Black-white differences in the stage at presentation of prostate cancer in the District of Columbia. Urology 1995; 46:71–77.
  19. Misra-Hebert AD. Physician cultural competence: cross-cultural communication improves care. Cleve Clin J Med 2003; 70:289,293,296–298.
  20. Powell I, Sakr W, Weiss L, et al. Prostate cancer is biologically more aggressive among African Americans than Caucasian men under age 70: hypothesis supported by autopsy and SEER data. Program and abstracts from the American Urological Association 95th Annual Meeting; April 29–May 4, 2000: Atlanta, GA.
  21. Powell IJ, Bock CH, Ruterbusch JJ, Sakr W. Evidence supports a faster growth rate and/or earlier transformation to clinically significant prostate cancer in black than in white American men, and influences racial progression and mortality disparity. J Urol 2010; 183:1792–1796.
  22. Kim HS, Moreira DM, Jayachandran J, et al. Prostate biopsies from black men express higher levels of aggressive disease biomarkers than prostate biopsies from white men. Prostate Cancer Prostatic Dis 2011; 14:262–265.
  23. Duffy MJ. Prostate-specific antigen: does the current evidence support its use in prostate cancer screening? Ann Clin Biochem 2011; 48:310–316.
  24. Andriole GL, Crawford ED, Grubb RL, et al; PLCO Project Team. Mortality results from a randomized prostate-cancer screening trial. N Engl J Med 2009; 360:1310–1319.
  25. Crawford ED, Grubb R, Black A, et al. Comorbidity and mortality results from a randomized prostate cancer screening trial. J Clin Oncol 2011; 29:355–361.
  26. Schröder FH, Hugosson J, Roobol MJ, et al; ERSPC Investigators. Screening and prostate-cancer mortality in a randomized European study. N Engl J Med 2009; 360:1320–1328.
  27. Hugosson J, Carlsson S, Aus G, et al. Mortality results from the Göteborg randomised population-based prostate-cancer screening trial. Lancet Oncol 2010; 11:725–732.
  28. Chornokur G, Dalton K, Borysova ME, Kumar NB. Disparities at presentation, diagnosis, treatment, and survival in African American men, affected by prostate cancer. Prostate 2011; 71:985–997.
  29. Boyd MD, Weinrich SP, Weinrich M, Norton A. Obstacles to prostate cancer screening in African-American men. J Natl Black Nurses Assoc 2001; 12:1–5.
  30. Freedland SJ, Isaacs WB. Explaining racial differences in prostate cancer in the United States: sociology or biology? Prostate 2005; 62:243–252.
  31. Ross LE, Berkowitz Z, Ekwueme DU. Use of the prostate-specific antigen test among U.S. men: findings from the 2005 National Health Interview Survey. Cancer Epidemiol Biomarkers Prev 2008; 17:636–644.
  32. Hosain GM, Sanderson M, Du XL, Chan W, Strom SS. Racial/ethnic differences in predictors of PSA screening in a tri-ethnic population. Cent Eur J Public Health 2011; 19:30–34.
  33. Carpenter WR, Howard DL, Taylor YJ, Ross LE, Wobker SE, Godley PA. Racial differences in PSA screening interval and stage at diagnosis. Cancer Causes Control 2010; 21:1071–1080.
  34. Betancourt JR, Maina AW. The Institute of Medicine report “Unequal Treatment”: implications for academic health centers. Mt Sinai J Med 2004; 71:314–321.
  35. Patel K, Kenerson D, Wang H, et al. Factors influencing prostate cancer screening in low-income African Americans in Tennessee. J Health Care Poor Underserved 2010; 21(suppl 1):114–126.
  36. Modlin CS. Culture, race, and disparities in health care. Cleve Clin J Med 2003; 70:283–288.
  37. Kyle C, Ewing T, Wu XC, et al. Statewide analysis of serum prostate specific antigen levels in Louisiana men without prostate cancer. J La State Med Soc 2004; 156:319–323.
  38. Vijayakumar S, Winter K, Sause W, et al. Prostate-specific antigen levels are higher in African-American than in white patients in a multicenter registration study: results of RTOG 94-12. Int J Radiat Oncol Biol Phys 1998; 40:17–25.
  39. Chang BL, Spangler E, Gallagher S, et al. Validation of genome-wide prostate cancer associations in men of African descent. Cancer Epidemiol Biomarkers Prev 2011; 20:23–32.
  40. National Comprehensive Cancer Network (NCCN). NCCN Stresses Importance of PSA Testing in High-Risk Men. http://www.nccn.org/about/news/newsinfo.asp?NewsID=218. Accessed April 2, 2012.
  41. National Cancer Institute. Prostate-Specific Antigen (PSA) Test. http://www.cancer.gov/cancertopics/factsheet/detection/PSA. Accessed April 2, 2012.
  42. Duggan D, Zheng SL, Knowlton M, et al. Two genome-wide association studies of aggressive prostate cancer implicate putative prostate tumor suppressor gene DAB2IP. Natl Cancer Inst 2007; 99:1836–1844.
  43. Grossfeld GD, Latini DM, Downs T, Lubeck DP, Mehta SS, Carroll PR. Is ethnicity an independent predictor of prostate cancer recurrence after radical prostatectomy? J Urol 2002; 168:2510–2515.
  44. Hoffman RM, Harlan LC, Klabunde CN, et al. Racial differences in initial treatment for clinically localized prostate cancer. Results from the prostate cancer outcomes study. J Gen Intern Med 2003; 18:845–853.
  45. Polednak AP. Prostate cancer treatment in black and white men: the need to consider both stage at diagnosis and socioeconomic status. J Natl Med Assoc 1998; 90:101–104.
  46. Merrill RM, Lyon JL. Explaining the difference in prostate cancer mortality rates between white and black men in the United States. Urology 2000; 55:730–735.
  47. Tewari AK, Gold HT, Demers RY, et al. Effect of socioeconomic factors on long-term mortality in men with clinically localized prostate cancer. Urology 2009; 73:624–630.
  48. White A, Coker AL, Du XL, Eggleston KS, Williams M. Racial/ethnic disparities in survival among men diagnosed with prostate cancer in Texas. Cancer 2011; 117:1080–1088.
  49. Moses KA, Paciorek AT, Penson DF, Carroll PR, Master VA. Impact of ethnicity on primary treatment choice and mortality in men with prostate cancer: data from CaPSURE. J Clin Oncol 2010; 28:1069–1074.
  50. Demers RY, Tiwari A, Wei J, Weiss LK, Severson RK, Montie J. Trends in the utilization of androgen-deprivation therapy for patients with prostate carcinoma suggest an effect on mortality. Cancer 2001; 92:2309–2317.
  51. Hsing AW, Chokkalingam AP. Prostate cancer epidemiology. Front Biosci 2006; 11:1388–1413.
  52. Schwartz K, Powell IJ, Underwood W, George J, Yee C, Banerjee M. Interplay of race, socioeconomic status, and treatment on survival of patients with prostate cancer. Urology 2009; 74:1296–1302.
  53. Hayn MH, Orom H, Shavers VL, et al. Racial/ethnic differences in receipt of pelvic lymph node dissection among men with localized/regional prostate cancer. Cancer 2011. [Epub ahead of print]
  54. Du XL, Lin CC, Johnson NJ, Altekruse S. Effects of individual-level socioeconomic factors on racial disparities in cancer treatment and survival: findings from the National Longitudinal Mortality Study, 1979–2003. Cancer 2011; 117:3242–3251.
  55. Winkfield KM, Chen MH, Dosoretz DE, et al. Race and survival following brachytherapy-based treatment for men with localized or locally advanced adenocarcinoma of the prostate. Int J Radiat Oncol Biol Phys 20115; 81:e345–e350.
  56. Fowler JE, Terrell F. Survival in blacks and whites after treatment for localized prostate cancer. J Urol 1996; 156:133–136.
  57. Tewari A, Horninger W, Badani KK, et al. Racial differences in serum prostate-specific antigen (PSA) doubling time, histopathological variables and long-term PSA recurrence between African-American and white American men undergoing radical prostatectomy for clinically localized prostate cancer. BJU Int 2005; 96:29–33.
  58. Bozeman C, Williams BJ, Whatley T, Crow A, Eastham J. Clinical and biopsy specimen features in black and white men with clinically localized prostate cancer. South Med J 2000; 93:400–402.
  59. Delongchamps NB, Singh A, Haas GP. Epidemiology of prostate cancer in Africa: another step in the understanding of the disease? Curr Probl Cancer 2007; 31:226–236.
  60. Quinn M, Babb P. Patterns and trends in prostate cancer incidence, survival, prevalence and mortality. Part I: international comparisons. BJU Int 2002; 90:162–173.
  61. Muller DC, Severi G, Baglietto L, et al. Dietary patterns and prostate cancer risk. Cancer Epidemiol Biomarkers Prev 2009; 18:3126–3129.
  62. Alexander DD, Mink PJ, Cushing CA, Sceurman B. A review and meta-analysis of prospective studies of red and processed meat intake and prostate cancer. Nutr J 2010; 9:50.
  63. Gonzalez CA, Riboli E. Diet and cancer prevention: contributions from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Eur J Cancer 2010; 46:2555–2562.
  64. Rodriguez C, McCullough ML, Mondul AM, et al. Calcium, dairy products, and risk of prostate cancer in a prospective cohort of United States men. Cancer Epidemiol Biomarkers Prev 2003; 12:597–603.
  65. McCarty MF. Mortality from Western cancers rose dramatically among African-Americans during the 20th century: are dietary animal products to blame? Med Hypotheses 2001; 57:169–174.
  66. Rodriguez C, Freedland SJ, Deka A, et al. Body mass index, weight change, and risk of prostate cancer in the Cancer Prevention Study II Nutrition Cohort. Cancer Epidemiol Biomarkers Prev 2007; 16:63–69.
  67. Spangler E, Zeigler-Johnson CM, Coomes M, Malkowicz SB, Wein A, Rebbeck TR. Association of obesity with tumor characteristics and treatment failure of prostate cancer in African-American and European American men. J Urol 2007; 178:1939–1944.
  68. Lippman SM, Klein EA, Goodman PJ, et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2009; 301:39–51.
  69. Oakley-Girvan I, Feldman D, Eccleshall TR, et al. Risk of early-onset prostate cancer in relation to germ line polymorphisms of the vitamin D receptor. Cancer Epidemiol Biomarkers Prev 2004; 13:1325–1330.
  70. Gilbert R, Martin RM, Beynon R, et al. Associations of circulating and dietary vitamin D with prostate cancer risk: a systematic review and dose-response meta-analysis. Cancer Causes Control 2011; 22:319–340.
  71. Gandini S, Boniol M, Haukka J, et al. Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. Int J Cancer 2011; 128:1414–1424.
  72. Yin L, Raum E, Haug U, Arndt V, Brenner H. Meta-analysis of longitudinal studies: serum vitamin D and prostate cancer risk. Cancer Epidemiol 2009; 33:435–445.
  73. McCormick DL, Johnson WD, Bosland MC, Lubet RA, Steele VE. Chemoprevention of rat prostate carcinogenesis by soy isoflavones and by Bowman-Birk inhibitor. Nutr Cancer 2007; 57:184–193.
  74. Belpomme D, Irigaray P, Ossondo M, Vacque D, Martin M. Prostate cancer as an environmental disease: an ecological study in the French Caribbean islands, Martinique and Guadeloupe. Int J Oncol 2009; 34:1037–1044.
  75. Ramis R, Diggle P, Cambra K, López-Abente G. Prostate cancer and industrial pollution. Risk around putative focus in a multi-source scenario. Environ Int 2011; 37:577–585.
  76. Dey S, Zhang Z, Hablas A, et al. Geographic patterns of cancer in the population-based registry of Egypt: possible links to environmental exposures. Cancer Epidemiol 2011; 35:254–264.
  77. Watters JL, Park Y, Hollenbeck A, Schatzkin A, Albanes D. Cigarette smoking and prostate cancer in a prospective US cohort study. Cancer Epidemiol Biomarkers Prev 2009; 18:2427–2435.
  78. Orsini N, Bellocco R, Bottai M, et al. A prospective study of lifetime physical activity and prostate cancer incidence and mortality. Br J Cancer 2009; 101:1932–1938.
References
  1. Altekruse SF, Kosary CL, Krapcho M, et al. SEER Cancer Statistics Review, 1975–2007, National Cancer Institute. Bethesda, MD. http://seer.cancer.gov/csr/1975_2007/, based on November 2009 SEER data submission, posted to the SEER web site, 2010. Accessed April 2, 2011.
  2. Arias E. United States life tables, 2007. National vital statistics reports; vol 59 no 9. Hyattsville, MD: National Center for Health Statistics. 2011.
  3. Klein JB, Nguyen CT, Saffore L, Modlin C, Modlin CS. Racial disparities in urologic health care. J Natl Med Assoc 2010; 102:108–117.
  4. Wells TS, Bukowinski AT, Smith TC, et al. Racial differences in prostate cancer risk remain among US servicemen with equal access to care. Prostate 2010; 70:727–734.
  5. Smedley BD, Stith AY, Nelson AR, editors. Unequal Treatment: Confronting Racial and Ethnic Disparities in Health Care. Institute of Medicine. National Academy Press; 2002.
  6. Odedina FT, Akinremi TO, Chinegwundoh F, et al. Prostate cancer disparities in black men of African descent: a comparative literature review of prostate cancer burden among black men in the United States, Caribbean, United Kingdom, and West Africa. Infect Agent Cancer 2009; 4(suppl 1):S2.
  7. Okobia MN, Zmuda JM, Ferrell RE, Patrick AL, Bunker CH. Chromosome 8q24 variants are associated with prostate cancer risk in a high risk population of African ancestry. Prostate 2011; 71:1054–1063.
  8. Haiman CA, Chen GK, Blot WJ, et al. Characterizing genetic risk at known prostate cancer susceptibility loci in African Americans. PLoS Genet 2011; 7:e1001387.
  9. Freedman ML, Haiman CA, Patterson N, et al. Admixture mapping identifies 8q24 as a prostate cancer risk locus in African-American men. Proc Natl Acad Sci U S A 2006; 103:14068–14073.
  10. Chang BL, Isaacs SD, Wiley KE, et al. Genome-wide screen for prostate cancer susceptibility genes in men with clinically significant disease. Prostate 2005; 64:356–361.
  11. Hatcher D, Daniels G, Osman I, Lee P. Molecular mechanisms involving prostate cancer racial disparity. Am J Transl Res 2009; 1:235–248.
  12. Robbins CM, Hooker S, Kittles RA, Carpten JD. EphB2 SNPs and sporadic prostate cancer risk in African American men. PLoS One 2011; 6:e19494.
  13. American Cancer Society. Cancer Facts & Figures for African Americans 2009–2010. http://www.cancer.org/acs/groups/content/@nho/documents/document/cffaa20092010pdf.pdf. Accessed April 2, 2012.
  14. Ayanian JZ, Udvarhelyi IS, Gatsonis CA, Pashos CL, Epstein AM. Racial differences in the use of revascularization procedures after coronary angiography. JAMA 1993; 269:2642–2646.
  15. Fine MJ, Ibrahim SA, Thomas SB. The role of race and genetics in health disparities research. Am J Public Health 2005; 95:2125–2128.
  16. Horner RD, Oddone EZ, Matchar DB. Theories explaining racial differences in the utilization of diagnostic and therapeutic procedures for cerebrovascular disease. Milbank Q 1995; 73:443–462.
  17. Juckett G. Cross-cultural medicine. Am Fam Physician 2005; 72:2267–2274.
  18. Ndubuisi SC, Kofie VY, Andoh JY, Schwartz EM. Black-white differences in the stage at presentation of prostate cancer in the District of Columbia. Urology 1995; 46:71–77.
  19. Misra-Hebert AD. Physician cultural competence: cross-cultural communication improves care. Cleve Clin J Med 2003; 70:289,293,296–298.
  20. Powell I, Sakr W, Weiss L, et al. Prostate cancer is biologically more aggressive among African Americans than Caucasian men under age 70: hypothesis supported by autopsy and SEER data. Program and abstracts from the American Urological Association 95th Annual Meeting; April 29–May 4, 2000: Atlanta, GA.
  21. Powell IJ, Bock CH, Ruterbusch JJ, Sakr W. Evidence supports a faster growth rate and/or earlier transformation to clinically significant prostate cancer in black than in white American men, and influences racial progression and mortality disparity. J Urol 2010; 183:1792–1796.
  22. Kim HS, Moreira DM, Jayachandran J, et al. Prostate biopsies from black men express higher levels of aggressive disease biomarkers than prostate biopsies from white men. Prostate Cancer Prostatic Dis 2011; 14:262–265.
  23. Duffy MJ. Prostate-specific antigen: does the current evidence support its use in prostate cancer screening? Ann Clin Biochem 2011; 48:310–316.
  24. Andriole GL, Crawford ED, Grubb RL, et al; PLCO Project Team. Mortality results from a randomized prostate-cancer screening trial. N Engl J Med 2009; 360:1310–1319.
  25. Crawford ED, Grubb R, Black A, et al. Comorbidity and mortality results from a randomized prostate cancer screening trial. J Clin Oncol 2011; 29:355–361.
  26. Schröder FH, Hugosson J, Roobol MJ, et al; ERSPC Investigators. Screening and prostate-cancer mortality in a randomized European study. N Engl J Med 2009; 360:1320–1328.
  27. Hugosson J, Carlsson S, Aus G, et al. Mortality results from the Göteborg randomised population-based prostate-cancer screening trial. Lancet Oncol 2010; 11:725–732.
  28. Chornokur G, Dalton K, Borysova ME, Kumar NB. Disparities at presentation, diagnosis, treatment, and survival in African American men, affected by prostate cancer. Prostate 2011; 71:985–997.
  29. Boyd MD, Weinrich SP, Weinrich M, Norton A. Obstacles to prostate cancer screening in African-American men. J Natl Black Nurses Assoc 2001; 12:1–5.
  30. Freedland SJ, Isaacs WB. Explaining racial differences in prostate cancer in the United States: sociology or biology? Prostate 2005; 62:243–252.
  31. Ross LE, Berkowitz Z, Ekwueme DU. Use of the prostate-specific antigen test among U.S. men: findings from the 2005 National Health Interview Survey. Cancer Epidemiol Biomarkers Prev 2008; 17:636–644.
  32. Hosain GM, Sanderson M, Du XL, Chan W, Strom SS. Racial/ethnic differences in predictors of PSA screening in a tri-ethnic population. Cent Eur J Public Health 2011; 19:30–34.
  33. Carpenter WR, Howard DL, Taylor YJ, Ross LE, Wobker SE, Godley PA. Racial differences in PSA screening interval and stage at diagnosis. Cancer Causes Control 2010; 21:1071–1080.
  34. Betancourt JR, Maina AW. The Institute of Medicine report “Unequal Treatment”: implications for academic health centers. Mt Sinai J Med 2004; 71:314–321.
  35. Patel K, Kenerson D, Wang H, et al. Factors influencing prostate cancer screening in low-income African Americans in Tennessee. J Health Care Poor Underserved 2010; 21(suppl 1):114–126.
  36. Modlin CS. Culture, race, and disparities in health care. Cleve Clin J Med 2003; 70:283–288.
  37. Kyle C, Ewing T, Wu XC, et al. Statewide analysis of serum prostate specific antigen levels in Louisiana men without prostate cancer. J La State Med Soc 2004; 156:319–323.
  38. Vijayakumar S, Winter K, Sause W, et al. Prostate-specific antigen levels are higher in African-American than in white patients in a multicenter registration study: results of RTOG 94-12. Int J Radiat Oncol Biol Phys 1998; 40:17–25.
  39. Chang BL, Spangler E, Gallagher S, et al. Validation of genome-wide prostate cancer associations in men of African descent. Cancer Epidemiol Biomarkers Prev 2011; 20:23–32.
  40. National Comprehensive Cancer Network (NCCN). NCCN Stresses Importance of PSA Testing in High-Risk Men. http://www.nccn.org/about/news/newsinfo.asp?NewsID=218. Accessed April 2, 2012.
  41. National Cancer Institute. Prostate-Specific Antigen (PSA) Test. http://www.cancer.gov/cancertopics/factsheet/detection/PSA. Accessed April 2, 2012.
  42. Duggan D, Zheng SL, Knowlton M, et al. Two genome-wide association studies of aggressive prostate cancer implicate putative prostate tumor suppressor gene DAB2IP. Natl Cancer Inst 2007; 99:1836–1844.
  43. Grossfeld GD, Latini DM, Downs T, Lubeck DP, Mehta SS, Carroll PR. Is ethnicity an independent predictor of prostate cancer recurrence after radical prostatectomy? J Urol 2002; 168:2510–2515.
  44. Hoffman RM, Harlan LC, Klabunde CN, et al. Racial differences in initial treatment for clinically localized prostate cancer. Results from the prostate cancer outcomes study. J Gen Intern Med 2003; 18:845–853.
  45. Polednak AP. Prostate cancer treatment in black and white men: the need to consider both stage at diagnosis and socioeconomic status. J Natl Med Assoc 1998; 90:101–104.
  46. Merrill RM, Lyon JL. Explaining the difference in prostate cancer mortality rates between white and black men in the United States. Urology 2000; 55:730–735.
  47. Tewari AK, Gold HT, Demers RY, et al. Effect of socioeconomic factors on long-term mortality in men with clinically localized prostate cancer. Urology 2009; 73:624–630.
  48. White A, Coker AL, Du XL, Eggleston KS, Williams M. Racial/ethnic disparities in survival among men diagnosed with prostate cancer in Texas. Cancer 2011; 117:1080–1088.
  49. Moses KA, Paciorek AT, Penson DF, Carroll PR, Master VA. Impact of ethnicity on primary treatment choice and mortality in men with prostate cancer: data from CaPSURE. J Clin Oncol 2010; 28:1069–1074.
  50. Demers RY, Tiwari A, Wei J, Weiss LK, Severson RK, Montie J. Trends in the utilization of androgen-deprivation therapy for patients with prostate carcinoma suggest an effect on mortality. Cancer 2001; 92:2309–2317.
  51. Hsing AW, Chokkalingam AP. Prostate cancer epidemiology. Front Biosci 2006; 11:1388–1413.
  52. Schwartz K, Powell IJ, Underwood W, George J, Yee C, Banerjee M. Interplay of race, socioeconomic status, and treatment on survival of patients with prostate cancer. Urology 2009; 74:1296–1302.
  53. Hayn MH, Orom H, Shavers VL, et al. Racial/ethnic differences in receipt of pelvic lymph node dissection among men with localized/regional prostate cancer. Cancer 2011. [Epub ahead of print]
  54. Du XL, Lin CC, Johnson NJ, Altekruse S. Effects of individual-level socioeconomic factors on racial disparities in cancer treatment and survival: findings from the National Longitudinal Mortality Study, 1979–2003. Cancer 2011; 117:3242–3251.
  55. Winkfield KM, Chen MH, Dosoretz DE, et al. Race and survival following brachytherapy-based treatment for men with localized or locally advanced adenocarcinoma of the prostate. Int J Radiat Oncol Biol Phys 20115; 81:e345–e350.
  56. Fowler JE, Terrell F. Survival in blacks and whites after treatment for localized prostate cancer. J Urol 1996; 156:133–136.
  57. Tewari A, Horninger W, Badani KK, et al. Racial differences in serum prostate-specific antigen (PSA) doubling time, histopathological variables and long-term PSA recurrence between African-American and white American men undergoing radical prostatectomy for clinically localized prostate cancer. BJU Int 2005; 96:29–33.
  58. Bozeman C, Williams BJ, Whatley T, Crow A, Eastham J. Clinical and biopsy specimen features in black and white men with clinically localized prostate cancer. South Med J 2000; 93:400–402.
  59. Delongchamps NB, Singh A, Haas GP. Epidemiology of prostate cancer in Africa: another step in the understanding of the disease? Curr Probl Cancer 2007; 31:226–236.
  60. Quinn M, Babb P. Patterns and trends in prostate cancer incidence, survival, prevalence and mortality. Part I: international comparisons. BJU Int 2002; 90:162–173.
  61. Muller DC, Severi G, Baglietto L, et al. Dietary patterns and prostate cancer risk. Cancer Epidemiol Biomarkers Prev 2009; 18:3126–3129.
  62. Alexander DD, Mink PJ, Cushing CA, Sceurman B. A review and meta-analysis of prospective studies of red and processed meat intake and prostate cancer. Nutr J 2010; 9:50.
  63. Gonzalez CA, Riboli E. Diet and cancer prevention: contributions from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Eur J Cancer 2010; 46:2555–2562.
  64. Rodriguez C, McCullough ML, Mondul AM, et al. Calcium, dairy products, and risk of prostate cancer in a prospective cohort of United States men. Cancer Epidemiol Biomarkers Prev 2003; 12:597–603.
  65. McCarty MF. Mortality from Western cancers rose dramatically among African-Americans during the 20th century: are dietary animal products to blame? Med Hypotheses 2001; 57:169–174.
  66. Rodriguez C, Freedland SJ, Deka A, et al. Body mass index, weight change, and risk of prostate cancer in the Cancer Prevention Study II Nutrition Cohort. Cancer Epidemiol Biomarkers Prev 2007; 16:63–69.
  67. Spangler E, Zeigler-Johnson CM, Coomes M, Malkowicz SB, Wein A, Rebbeck TR. Association of obesity with tumor characteristics and treatment failure of prostate cancer in African-American and European American men. J Urol 2007; 178:1939–1944.
  68. Lippman SM, Klein EA, Goodman PJ, et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2009; 301:39–51.
  69. Oakley-Girvan I, Feldman D, Eccleshall TR, et al. Risk of early-onset prostate cancer in relation to germ line polymorphisms of the vitamin D receptor. Cancer Epidemiol Biomarkers Prev 2004; 13:1325–1330.
  70. Gilbert R, Martin RM, Beynon R, et al. Associations of circulating and dietary vitamin D with prostate cancer risk: a systematic review and dose-response meta-analysis. Cancer Causes Control 2011; 22:319–340.
  71. Gandini S, Boniol M, Haukka J, et al. Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. Int J Cancer 2011; 128:1414–1424.
  72. Yin L, Raum E, Haug U, Arndt V, Brenner H. Meta-analysis of longitudinal studies: serum vitamin D and prostate cancer risk. Cancer Epidemiol 2009; 33:435–445.
  73. McCormick DL, Johnson WD, Bosland MC, Lubet RA, Steele VE. Chemoprevention of rat prostate carcinogenesis by soy isoflavones and by Bowman-Birk inhibitor. Nutr Cancer 2007; 57:184–193.
  74. Belpomme D, Irigaray P, Ossondo M, Vacque D, Martin M. Prostate cancer as an environmental disease: an ecological study in the French Caribbean islands, Martinique and Guadeloupe. Int J Oncol 2009; 34:1037–1044.
  75. Ramis R, Diggle P, Cambra K, López-Abente G. Prostate cancer and industrial pollution. Risk around putative focus in a multi-source scenario. Environ Int 2011; 37:577–585.
  76. Dey S, Zhang Z, Hablas A, et al. Geographic patterns of cancer in the population-based registry of Egypt: possible links to environmental exposures. Cancer Epidemiol 2011; 35:254–264.
  77. Watters JL, Park Y, Hollenbeck A, Schatzkin A, Albanes D. Cigarette smoking and prostate cancer in a prospective US cohort study. Cancer Epidemiol Biomarkers Prev 2009; 18:2427–2435.
  78. Orsini N, Bellocco R, Bottai M, et al. A prospective study of lifetime physical activity and prostate cancer incidence and mortality. Br J Cancer 2009; 101:1932–1938.
Issue
Cleveland Clinic Journal of Medicine - 79(5)
Issue
Cleveland Clinic Journal of Medicine - 79(5)
Page Number
313-320
Page Number
313-320
Publications
Cleveland Clinic Journal of Medicine
Publications
Cleveland Clinic Journal of Medicine
Topics
Oncology
Men's Health
Article Type
Article
Display Headline
Disparities in prostate cancer in African American men: What primary care physicians can do
Display Headline
Disparities in prostate cancer in African American men: What primary care physicians can do
Sections
Addressing Disparities in Health Care
Inside the Article

KEY POINTS

  • African American men have the dual disadvantages of being less likely to receive adequate care and also, possibly, of having biological differences that make them more prone to prostate cancer and more-aggressive cancer.
  • Prostate-specific antigen (PSA) cutoff levels have not been officially modified according to race, but we believe primary care physicians should have a lower threshold for referring African American men who have a suspiciously high PSA level for further urologic evaluation.
  • A healthy lifestyle, with a low-fat diet, healthy body mass index, and daily exercise, may decrease the risk of prostate cancer, among other benefits.
  • Primary care physicians, who are often the gatekeepers to care, play a key role in educating and screening their patients.
Disallow All Ads
Alternative CME
Article PDF Media
Subscribe to Ina Wu, MD