Use of nonsteroidal antiinflammatory drugs and risk of breast cancer: the Case-Control Surveillance Study revisited.

Several studies have suggested that use of nonsteroidal antiinflammatory drugs (NSAIDs) may reduce the risk of breast cancer. Reductions in risk may vary according to the hormone receptor status of the tumor or the type of NSAID used. The authors extended a previous US hospital-based case-control study (the Case-Control Surveillance Study) to include 444 additional cases, for a total of 7,006 incident breast cancer cases (1976-2002). They examined the relation between regular NSAID use and breast cancer risk using logistic regression to adjust for confounding. The odds ratio for regular use of NSAIDs was 0.78 (95% confidence interval: 0.63, 0.97), and a trend of decreasing risk with increasing duration of use was statistically significant (p for trend = 0.02). The inverse association with regular use of NSAIDs was stronger among premenopausal women (odds ratio = 0.62). The overall odds ratios for regular use of aspirin and ibuprofen were 0.86 and 0.85, respectively. The effect of NSAID use on breast cancer risk did not vary according to the hormone receptor status of the tumor. In conclusion, long-term regular use of NSAIDs was associated with decreased risk of breast cancer. The type of NSAID used or the hormone receptor status of the tumor did not modify the effect.