NONSTEROIDAL ANTIINFLAMMATORY DRUGS AND COLORECTAL-CANCER

Background. The association between the use of nonsteroidal antiinflam matory drugs (NSAID) and large bowel cancer was examined in a hospital -based case-control study of 511 patients with colorectal cancer and 5 00 age-sex matched control subjects. Methods. Regular NSAID use was de fined as at least 3 times per week for 1 or more years before the date of hospital admission. Odds ratios (OR) were calculated by the durati on of NSAID use and according to the medical reasons given for taking NSAIDs. Results. The prevalences of regular NSAID use were 15% for mal e patients, 8% for female patients, and 20% for control subjects. Over all, NSAID use was associated with a statistically significant risk re duction in men (OR = 0.64; 95% confidence interval [CI], 0.42-0.97) an d in women (OR = 0.32; 95% CI, 0.18-0.57). The estimate decreased with duration among men but increased with duration among women. The risk reduction among patients who took NSAIDs to prevent heart disease was 0.67 (95% CI, 0.38-1.13) for men and 0.43 (95% CI, 0.12-1.59) for wome n. For treating headache pain, the OR was 0.5 (95% CI, 0.23-1.09) for men and 0.64 (95% CI, 0.25-1.62) for women. The use of NSAID was not f ound to be associated with the stage of cancer at diagnosis. The OR fo r daily acetaminophen use was 1.07 (95% CI, 0.35-3.23) for men and 0.5 9 (95% CI, 0.27-1.25) for women. Conclusions. The regular use of NSAID s was associated with an overall significant risk reduction of colorec tal cancer in men and in women. Among female patients, the greater pro tective effect associated with short term NSAID use compared with long term NSAID use may reflect a sampling bias.