Family History and Age at Initiation of Colorectal Cancer Screening

OBJECTIVES: To review and combine the best available epidemiological evidence, by sex and age, that may help decision and policy makers form recommendations as to how much earlier colorectal cancer (CRC) screening should be initiated among people with a family history of CRC than among average-risk people. PATIENTS AND METHODS: Combining population-based cancer registry and health interview survey data from the United States and results of a recent meta-analysis of epidemiological studies, we estimated cumulative incidence of CRC within subsequent 10 yr (Cl-10) at various ages among men and women with and without a family history of CRC. We estimated both the Cl-10 levels reached in average-risk 45-, 50-, 55-, and 60-yr-old men and women and the age at which the same Cl-10 levels are reached in men and women with a history of CRC in a first-degree relative. RESULTS: Despite major differences in CRC risk by sex, and despite the strong age gradient in relative risk associated with a positive family history, "risk advancement periods" for those with a family history were consistently found to be between 9 and 11 yr for both sexes and at all four ages assessed. CONCLUSION: Advancement of first CRC screening by 10 yr among both men and women with a family history of CRC compared to the average-risk population (e.g., from 50 to 40 yr of age) appears to be a reasonable, evidence-based recommendation.