The results of a study published in the July 13 issue of JAMA have revealed that throughout adulthood considerable changes occur in a patient's family history related to colorectal, breast, and prostate cancer between the ages of 30 and 50 years. This calls for more frequent cancer screening with the patient's family history of cancer being reviewed every 5 to 10 years.
According to background information in the article,
"One of the most effective tools to identify individuals at increased risk of cancer is to ascertain their family history. For example, having one or more close relatives with colorectal cancer increases risk from 2-fold to 6-fold. Individuals at increased risk of colorectal, breast, or prostate cancer due to family history are recommended to begin screening for these cancers earlier and in some cases using more sensitive methods than average-risk individuals".
It is advised that clinicians, during primary care visits, must collect a comprehensive history of cancer in the family, including the age at which affected relatives (first- and second-degree) got diagnosed. It is not clear as to how often clinically significant changes in cancer family history occur over a time period.
Researcher Argyrios Ziogas, Ph.D., of the University of California-Irvine, and his team conducted a study to understand how often clinically significant changes in family history of various forms of cancer occur throughout adulthood. The study was conducted between 1999 and 2009 and comprised of baseline examinations and follow-up family history data from participants in the Cancer Genetics Network (CGN), which is a U.S. national population-based cancer registry.
Adults with a personal history, family history, or both of cancer enrolled in the CGN through population-based cancer registries participated in the study. 1,533, 617, and 163 participants were included in prospective analyses respectively. Retrospective colorectal, breast, and prostate cancer screening-specific analyses included 9,861, 2,547, and 1,817 participants, respectively. Median (midpoint) follow-up was 8 years. The primary outcomes measured included percentage of individuals with clinically significant family histories and rate of change over two periods: (1) retrospectively, from birth until CGN enrollment and (2) prospectively, from enrollment to last follow-up.
The scientists observed that on retrospective analysis the percentages of participants who were fitting the requirements for high-risk screening based on family history at ages 30 and 50 years, respectively, were as follows: for colorectal cancer, 2.1 percent and 7.1 percent; for breast cancer, 7.2 percent and 11.4 percent; and for prostate cancer, 0.9 percent and 2.0 percent. The researchers write,
"In prospective analysis, the numbers of participants who newly met criteria for high-risk screening based on family history per 100 persons followed up for 20 years were 2 for colorectal cancer, 6 for breast cancer, and 8 for prostate cancer. The rate of change in cancer family history was similar for colorectal and breast cancer between the 2 analyses".
"Both analyses demonstrate that clinically relevant family history changes substantially during early and middle adulthood, particularly for colorectal and breast cancer, for which the percentage recommended for high-risk screening increases 1.5- to 3-fold between ages 30 and 50 years."
Editorial: Recording, Interpreting, and Updating the Family History of Cancer
In an editorial add-on, researcher Louise S. Acheson, M.D., M.S., of Case Western Reserve University School of Medicine, Cleveland, states that such studies related to screening consider risks, benefits, costs, and lead time issue.
"It is plausible but still unknown whether family history increases the likelihood that breast cancers, prostate cancers, or colon adenomas found by screening are clinically significant. An increase in the incidence of false-positive results and test-associated complications is a cost and potential harm of increased screening based on familial risk. Although some prospective data on the benefits of cancer screening based on familial risk are available, many estimates rely on extrapolation from small studies of patients with high-penetrance hereditary cancer susceptibility or from screening older patients at equivalent levels of risk."
Source: Journal of the American Medical Association (JAMA)
Written by Barry Windsor