Actual and Perceived Risk of Colorectal Neoplasia in First-Degree Relatives of Patients with Colorectal Cancer

Individuals with a family history (FH) of colorectal cancer (CRC) are at increased risk of CRC. We aimed to assess the objective role and subjective perception of risk factors of colorectal neoplasia within this high-risk group.

Questionnaire and screening colonoscopy results were obtained from individuals aged 40-54 years with a reported FH of CRC in a first-degree relative in a multicenter cross-sectional study in Germany. Descriptive statistics characterized the cohort and distribution of risk factors. Multivariable logistic regression was used to derive adjusted odds ratios (aORs) and corresponding 95% confidence intervals (CIs) to evaluate factors associated with colorectal neoplasia and with subjectively perceived increased CRC-risk.

Among 922 participants, 220 (23.9%) were diagnosed with colorectal neoplasia, 63 (6.8%) of these being advanced lesions. Strong associations with advanced neoplasia were observed for obesity (aOR 2.44, 95% CI 1.12-5.22), smoking (aOR 1.47, 95% CI 1.14-1.88 per 10-pack-years) and physical activity <45 minutes per day (aOR 2.51, 95% CI 1.11-5.25). For smoking and physical activity, but not for obesity, similar associations were also seen with any colorectal neoplasia. No associations were seen with number and age at diagnosis of affected family members. By contrast, the latter factors, but none of the behavioral factors were strongly associated with subjectively perceived CRC-risk.

Within a cohort of individuals aged 40-54 years with a FH of CRC, obesity, smoking, and lack of physical activity represented the most prominent modifiable risk factors for the development of advanced colorectal neoplasia but did not significantly impact risk perception in these high-risk participants.