NONSTEROIDAL ANTIINFLAMMATORY DRUG-USE AND REDUCED RISK OF LARGE-BOWEL CARCINOMA

BACKGROUND. Animal experiments and epidemiologic data have suggested t hat the use of nonsteroidal antiinflammatory drugs (NSAIDs) may decrea se the incidence of large bowel carcinoma. Our purpose was to assess t he relation of the use of aspirin and nonaspirin NSAIDs with the risk of large bowel carcinoma. METHODS. A population-based case-control stu dy of colon and rectal carcinoma was conducted in Massachusetts from 1 992 to 1994. Data on NSAID use and risk factors for large bowel carcin oma were collected by interview from 1201 incident cases of large bowe l carcinoma and 1201 controls matched by age, gender, and area of resi dence. RESULTS. Regular NSAID use that continued into the year before diagnosis was associated with a significantly decreased relative risk estimate overall (0.7; 95% confidence interval [CI], 0.5-0.8) and amon g Stage II-IV tumors (0.6; 95% CI, 0.4-0.7). There was no reduction in risk for discontinued use. The inverse association with regular conti nuing use was present across age and gender and for both colon and rec tal carcinoma. Similar inverse associations were present for regular c ontinuing use of aspirin and nonaspirin NSAIDs. There was no significa nt evidence of a trend for the relative risk to decrease as the durati on of use increased, nor was there a trend across the dose of aspirin, which ranged from less than one-half of a 325 mg tablet per day to gr eater than or equal to 2 tablets per day. Discontinuation of use in re sponse to symptoms of carcinoma did not appear to explain the inverse association, nor did bias related to diagnosis of the carcinoma. CONCL USIONS. These data add to the growing body of evidence that suggests a protective effect of NSAIDs against large bowel carcinoma. (C) 1998 A merican Cancer Society.