Prostate cancers detected during screening are much more likely to be high risk when they affect black men and men aged 75 years or older.
Men over age 74 years were nine times more likely to have high-risk disease after a positive prostate-specific antigen test, and black men of all ages were twice as likely to have high-risk disease as were white men, based on a study of 4 years of data extracted from the Surveillance, Epidemiology and End Results (SEER) database.
The findings make the case for a more personalized approach to screening, Dr. Hong Zhang said at a press briefing during the 2013 Genitourinary Cancers Symposium.
Dr. Hong Zhang
Without prostate-specific antigen (PSA) screening, "we have no other way to detect prostate cancer sufficiently early to have the best chance of helping this group of high-risk patients," said Dr. Zhang of the University of Rochester (N.Y.).
The study brings a bit of context to current PSA screening guidelines, which are "all over the map," according to session moderator Dr. Bruce Roth of Washington University, St. Louis. In 2011, the United States Preventive Services Task Force determined that routine screening harms more men that it helps.
"The American Cancer Society recommends just screening older men and the USPTF recommends that nobody get screened," Dr. Roth said. Based on these results, the presumption that older men will die first of something other than their prostate cancer is not necessarily true. "In fact, a significant number of these men present with high-risk disease. Age is not the greatest determinant of who should and should not be screened."
During 2004-2008, 70,345 men were diagnosed with T1cN0M0 prostate cancer in SEER. Of these, 48% had low-risk disease (PSA less than 10 mg/L or Gleason score of 6 or less), 36% intermediate-risk disease (PSA between 10 mg/L and 20 mg/L or Gleason score 7), and 16% high-risk disease (PSA at least 20 mg/L, or Gleason score of 8 or higher).
The median age of patients with low-risk disease was 67 years; for those with intermediate-risk disease, median age was 70 years; and for high-risk disease, it was 72 years. Men 75 years or older accounted for 12% of the population, but for 24% of intermediate-risk and 26% of high-risk disease.
In a multivariate analysis, Dr. Zhang determined that, compared with younger men, those aged 75 years and older were almost five times more likely to have intermediate-risk disease and nine times more likely to have high-risk disease.
Blacks made up 13% of the low-risk category, 16% of the intermediate-risk category, and 18% of the high-risk category. Compared with whites, blacks were 1.5 times more likely to have intermediate-risk disease and twice as likely to have high-risk disease.
Dr. Zhang and Dr. Roth had no financial disclosures.