Underreporting of family history of colon cancer: Correlates and implications

Scientific advances in cancer genetics, risk counseling, and management of high-risk individuals require information about familial cancer history. Be cause some people may not report, or may be unaware of, cancer in their fam ilies, it is important to examine the extent of underreporting of family hi story. We mailed a survey to first-degree relatives of patients with histol ogically confirmed diagnoses of colorectal cancer (CRC) before age 60 (n = 426, 77% response rate). Analyses examined the extent of underreporting of family history and its predictors (demographics, cancer characteristics, kn owledge, and communication) and correlates (cancer worry, perceived risk). Logistic regression analysis was performed using generalized estimating equ ations to account for family clusters. Despite confirmed diagnosis of CRC i n a parent or sibling, 25.4% of respondents reported having no first-degree relative with colon cancer. In multivariate models, the most significant p redictor of awareness of a relative's CRC was the stage-at-diagnosis; also, males and those with low knowledge about colon cancer were significantly l ess aware, Awareness of a relative's CRC was associated with higher cancer worry and risk perception, and being a college graduate contributed indepen dently to increased risk perception. Sole dependence on mailed self-adminis tered questionnaires may lead to substantial underreporting of familial col on cancers, especially those that are in situ or localized.