A patient’s family history for breast and colorectal cancer changes substantially during early and middle adulthood, and making appropriate referrals for cancer screening requires keeping up to date with those changes, according to a report in the July 13 JAMA.
Overall, the percentage of patients who should be referred for screening because their family history puts them at high risk increases as much as threefold between the ages of 30 and 50, so family histories should be updated at least every 5-10 years, according to Argyrios Ziogas, Ph.D., of the University of California, Irvine, Genetic Epidemiology Research Institute and his associates (JAMA 2011;306:172-8).
"It is estimated that 22% of individuals have a family history that suggests familial or hereditary predisposition to cancer." However, until now, little has been studied regarding clinically relevant changes in family history over time.
"If a patient’s family history is not updated during early and middle adulthood, the opportunity may be missed to intervene with earlier or more intensive screening that maximizes the likelihood of detecting cancer at an early, treatable stage," they noted.
<a href="http://polldaddy.com/poll/5231627/">How often do ask patients about family history?</a>Previous research has documented that most primary care patients do not receive adequate assessment of familial cancer risks. Primary care physicians are likely to collect family history data at a patient’s first office visit, but do not adequately update that information in later visits. This is particularly important given that primary physicians are often the first – or only – caregivers to collect family health histories, and they are also the main source of referral for cancer screening, Dr. Ziogas and his colleagues said.
To determine how often family cancer histories should be updated, the researchers assessed how often patients’ family histories of breast and colorectal cancer changed throughout adulthood. They analyzed data on 16,724 subjects (plus 11,323 of their relatives) who were enrolled in the Cancer Genetics Network, a national U.S. registry established by the National Cancer Institute in 1998 for people with family histories of cancer.
The investigators performed one retrospective analysis of family histories, beginning on the day the subject enrolled in the registry and extending back to their birth, as well as one prospective analysis of family histories beginning on the day of enrollment and extending forward until the latest follow-up survey, a mean of 8 years later.
The retrospective analysis showed that at age 30 years, only 2% of the subjects would have met criteria for early colonoscopy screening based on their family history of colorectal cancer. But by age 50 years, this percentage increased to 7%, and by age 70, it increased to 11%.
Similarly, the retrospective analysis showed that only 7% of women at age 30 years would have met criteria for enhanced MRI scanning (rather than mammography) based on their family history of breast cancer, but that the percentage increased to 11% at age 50 and to 13% at ages 60 and older.
In the prospective analyses, 1% of the subjects had substantial changes in their family histories of colorectal cancer every 10 years, which would switch them from a low-risk to a high-risk category eligible for enhanced screening. Similarly, 3% of women had substantial changes in their family histories of breast cancer every 10 years, which would switch them from a low-risk to a high-risk category eligible for MRI scanning.
Overall, "we found a 5% chance that an individual’s colorectal cancer screening recommendation would change between ages 30 and 50 years based on family history and that 4% of women would become candidates for MRI screening," Dr. Ziogas and his associates wrote.
"We ... recommend that family history should be updated at least every 5-10 years to appropriately inform recommendations for cancer screening," they said.
This study was supported by the National Cancer Institute. No financial conflicts of interest were reported.