Aspirin, nonsteroidal anti‐inflammatory drugs, paracetamol and risk of endometrial cancer: A case–control study, systematic review and meta‐analysis

Annette S. Neill, Christina M. Nagle, Melinda M. Protani, Andreas Obermair, Amanda B. Spurdle, Penelope M. Webb, for the Australian National Endometrial Cancer Study Group

Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with reduced risk of a number of cancer types, however, previous studies of endometrial cancer have yielded inconclusive results. We analyzed data from the Australian National Endometrial Cancer Study (ANECS), a population-based case-control study (1,398 cases, 740 controls). We systematically reviewed all the evidence linking aspirin/NSAIDs use with endometrial cancer and conducted a meta-analysis. For ANECS, unconditional logistic regression was used to estimate odds ratios (OR) adjusting for potential confounders. For the systematic review, we searched Pubmed, Embase, Web of Science and conducted a review of citations from retrieved articles. The meta-analysis risk estimates were pooled using a random-effects model. In our case-control study, women who had ever used aspirin in the last 5 years had a significantly lower risk of endometrial cancer OR = 0.78 [95% confidence interval (CI): 0.63-0.97]. There was a significant inverse dose-response (p-trend <0.001) such that women who reported using ≥2 aspirin/week had almost half the risk OR = 0.54 (0.38-0.78). No significant associations were observed between use of half-aspirin/day, non-aspirin NSAIDs or paracetamol and endometrial cancer risk. The results were similar when examined by cancer subtype. Nine studies were included in the meta-analysis. The overall pooled risk estimate for any versus no use of aspirin was 0.87 (0.79-0.96) with no evidence of heterogeneity. The pooled risk estimate for obese women (BMI ≥ 30 kg/m(2) ) was 0.72 (0.58-0.90) but there was no association for non-obese women. Overall these results suggest that aspirin may reduce the risk of endometrial cancer, particularly among obese women.