Purpose: Family history of colorectal cancer may be a phenotype for numerous genetic mutations which increase colorectal cancer risk and may affect survival after diagnosis. We examined the relationship between self-reported first-degree family history of colorectal cancer and survival.
Methods: We identified female Wisconsin residents ages 20-74 with a new diagnosis of invasive colorectal cancer from two population-based case-control studies; 1,469 women were interviewed. Follow-up averaged 7.9 years. We performed multivariable Cox proportional hazards regressions to calculate adjusted hazard rate ratios [HR] and corresponding 95% confidence intervals [95% CI] for risk of death by family history.
Results: Of 1,391 cases with available first-degree family history, 481 were deceased, 268 due to colorectal cancer. In multivariable analyses, cases with any family history (N=262) had a statistically non-significant lower risk of death (HR 0.86, 95% CI 0.62, 1.20) compared to no family history (N=1,129). Cases with two or more affected family members (N=46) showed significantly lower risk of death when compared to women with no family history (HR 0.34, 95% CI 0.13, 0.92).
Conclusions: Although individuals with a colorectal cancer family history are diagnosed with the disease more often than the general population, these data suggest that survival from colorectal cancer may not be worse.