Updating family cancer history may change screening recommendations

Updating patients' family history of cancer during adulthood may lead to changes in recommended cancer screenings, according to a new study.

Researchers used data from the Cancer Genetics Network from 1999 to 2009 to determine how often changes in family history of cancer throughout adulthood could warrant changes in patients' own cancer screening. Included were 11,129 adults who had a personal history, family history, or both personal and family history of cancer. The study's main outcome measures were proportions of patients with clinically significant family histories and rate of change both retrospectively, defined as birth until enrollment in the network, and prospectively, defined as enrollment to last follow-up. The retrospective screening-specific analyses of colorectal, breast and prostate cancer included 9,861, 2,547 and 1,817 patients, while prospective analyses included 1,533, 617 and 163 patients, respectively. Median follow-up was 8 years. The study results appeared in the July 13 Journal of the American Medical Association.

In retrospective analyses, 2.1% and 7.1% of patients met high-risk criteria for colorectal cancer screening based on family history at age 30 years and at age 50 years, respectively. For breast cancer, percentages were 7.2% at 30 years and 11.4% at 50 years, while for prostate cancer percentages were 0.9% at 30 years and 2.0% at 50 years. Prospective analyses determined that 2 per 100 persons followed for 20 years met high-risk criteria for colorectal cancer screening based on updated family history between ages 30 and 50; for breast cancer and prostate cancer, these numbers were 6 and 8 per 100 persons followed for 20 years, respectively.

The authors noted that they didn't take personal medical history or previous cancer screening into account and did not consider criteria for genetic risk assessment, among other limitations. However, they found that between ages 30 and 50, there was a 5% chance that recommendations for colorectal cancer screening would change based on family history; they also found that 4% of women would become eligible for more intensive breast cancer screening with magnetic resonance imaging over the same period because of family history changes. The authors recommended that patients' family histories of cancer be updated every 5 to 10 years at minimum so that appropriate screening recommendations can be made.

An accompanying editorial recognized that family history is an important part of medical decision making but pointed out that risks, benefits and costs of screening must also be considered. “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,” the editorialist wrote. “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.”