Background: Observational studies have reported survival benefits associated with aspirin and non-aspirin non-steroidal anti-inflammatory drugs (NA-NSAIDs), especially new use post-diagnosis in women with ovarian cancer.
Methods: We investigated the association between NSAIDs and survival in women with epithelial ovarian cancer. We used data from the Ovarian cancer Prognosis and Lifestyle (OPAL) study, a prospective study of Australian women aged 18-79, diagnosed from 2012-2015 (follow-up=5-8 years). We measured 5-year overall (OS), cancer-specific (OVS) and progression-free survival (PFS) from date of starting primary cancer treatment (surgery or neoadjuvant chemotherapy) (pre-diagnosis analyses) or from 12 months after the start of therapy (post-diagnosis analyses) until the earliest of date of death/last follow-up/5 years. We used Cox regression to calculate adjusted hazard ratios (HR) and 95% confidence intervals (CI). We also applied inverse probability of treatment weighting (IPTW) to reduce bias due to confounding by indication.
Findings: We had pre-diagnosis data for 947 women and post-diagnosis data for 701 women. We observed approximately 30% improved survival associated with pre-diagnosis use of aspirin and NA-NSAIDs ≥4 days/week (frequent-use) compared to use <1/week. The association was close to null for those who used medications 1-3 days/week. Similarly, we saw a 30-40% improvement in OS, OVS and PFS associated with post-diagnosis use of aspirin and NA-NSAIDs, again driven by frequent use. When we restricted post-diagnosis users to new users or women who received chemotherapy, these results did not change markedly. Results from IPTW models were similar to adjusted models. We found no survival advantage associated with the use of paracetamol.
Interpretation: Our findings suggest aspirin and NA-NSAID use might improve survival in women with ovarian cancer. Larger cohorts or, preferably, a randomised controlled trial could clarify these findings.