Use of aspirin, other nonsteroidal anti-inflammatory drugs and acetaminophen and risk of endometrial cancer: The Epidemiology of Endometrial Cancer Consortium

Background - Regular use of aspirin has been associated with a reduced risk of cancer at several sites but the data for endometrial cancer are conflicting. Evidence regarding use of other analgesics is limited. Patients and methods - We pooled individual-level data from seven cohort and five case–control studies participating in the Epidemiology of Endometrial Cancer Consortium including 7120 women with endometrial cancer and 16 069 controls. For overall analyses, study-specific odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression and combined using random-effects meta-analysis; for stratified analyses, we used mixed-effects logistic regression with study as a random effect. Results - At least weekly use of aspirin and non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) was associated with an approximately 15% reduced risk of endometrial cancer among both overweight and obese women (OR = 0.86 [95% CI 0.76–0.98] and 0.86 [95% CI 0.76–0.97], respectively, for aspirin; 0.87 [95% CI 0.76–1.00] and 0.84 [0.74–0.96], respectively, for non-aspirin NSAIDs). There was no association among women of normal weight (body mass index 2, Pheterogeneity = 0.04 for aspirin, Pheterogeneity = 0.003 for NSAIDs). Among overweight and obese women, the inverse association with aspirin was stronger for use 2–6 times/week (OR = 0.81, 95% CI 0.68–0.96) than for daily use (0.91, 0.80–1.03), possibly because a high proportion of daily users use low-dose formulations. There was no clear association with use of acetaminophen. Conclusion - Our pooled analysis provides further evidence that use of standard-dose aspirin or other NSAIDs may reduce risk of endometrial cancer among overweight and obese women.