Background: We undertook the present analyses to determine whether family history of colorectal cancer in a parent or sibling modifies the inverse association of nonsteroidal anti-inflammatory drug (NSAID) use with colorectal cancer risk.
Methods: We used data from two case-control studies of colorectal cancer. The hospital-based Case Control Surveillance Study included 1526 patients with primary colorectal cancer, 4192 cancer controls and 6036 noncancer controls. A population-based study conducted in Massachusetts enrolled 1201 incident cases of colorectal cancer and 1201 community controls. Data on NSAID use and risk factors for colorectal cancer were collected by interview.
Results: In both studies there was a reduction in the odds ratios among subjects who used NSAIDs regularly continuing into the previous year, regardless of family history. In the Case Control Surveillance data, the odds ratio was 0.4 (95% CI 0.2-0.9) among subjects with a family history and 0.5 (95% CI 0.4-0.7) among subjects without a family history. The comparable odds ratios in the Massachusetts data were 0.5 (95% CI 0.3-0.9) and 0.7 (95% CI 0.6-0.9).
Conclusions: These data indicate that regular continuing NSAID use is associated with a reduced risk of colorectal cancer among persons with a family history of the disease, as well as those without such a history.