Barnard ME, et al. - Experts assessed whether the use of regular aspirin or non-aspirin nonsteroidal anti-inflammatory drug (NSAID) and use patterns are related to a lower risk of ovarian cancer. Overall, the investigators noted consistency of these results with those of case-control studies that showed a reduced risk of ovarian cancer among regular users of low-dose aspirin. They also observed an increased risk of ovarian cancer with long-term high-quantity use of other analgesics, particularly non-aspirin NSAIDs; however, this finding requires confirmation.

Methods

• Authors conducted this cohort study to evaluate NSAID use and ovarian cancer diagnosis data from 2 prospective cohorts: 93,664 women in the Nurses’ Health Study (NHS), who were followed up from 1980 to 2014, and 111,834 in the Nurses’ Health Study II (NHSII), who were followed up from 1989 to 2015.
• They completed the follow-up on June 30, 2014, for the NHS and June 30, 2015, for NHSII.
• They evaluated the data from June 13, 2016, to September 18, 2017.
• For each analgesic type (aspirin, low-dose aspirin, non-aspirin NSAIDs, and acetaminophen), they evaluated timing, duration, frequency, and number of tablets used; exposure information was updated every 2 to 4 years.
• They utilized Cox proportional hazards models to estimate hazard ratios (HRs) and 95% CIs for associations of aspirin, non-aspirin NSAIDs, and acetaminophen with risk of epithelial ovarian cancer.
• They noted all statistical tests to be 2-sided, with a significance level of .05.

Results

• In the NHS, the mean (SD) age at baseline (1980) was 45.9 (7.2) years, and 93% of participants identified as non-Hispanic white individuals.
• In the NHSII, the mean age at baseline (1989) was 34.2 (4.7) years, and 92% identified as non-Hispanic white individuals.
• In both cohorts, among the 205,498 women, there were 1,054 cases of incident epithelial ovarian cancer.
• Aspirin and ovarian cancer risk were not found to be significantly associated when current vs non-use of any aspirin was evaluated regardless of dose (HR, 0.99; 95% CI, 0.83-1.19).
• Nonetheless, while evaluating low-dose (≤ 100 mg) and standard-dose (325 mg) aspirin separately, an inverse association for low-dose aspirin (HR, 0.77; 95% CI, 0.61-0.96), but no association for standard-dose aspirin (HR, 1.17; 95% CI, 0.92-1.49) was observed.
• They noted positive association of current use of non-aspirin NSAIDs with risk of ovarian cancer compared with nonuse (HR, 1.19; 95% CI, 1.00-1.41), and significant positive trends for duration of use (P=0.02 for trend) and cumulative average tablets per week (P=0.03 for trend) were observed.
• There were no clear associations for the use of acetaminophen.