Data from colon, breast and prostate cancers suggest that aspirin users have reduced mortality. While the direct mechanism remains uncertain, aspirin can suppress the COX-dependent and independent pathways involved in tumor progression. We hypothesized that aspirin users with clear cell ovarian cancer would have improved survival outcomes. We performed a retrospective review of patients with clear cell ovarian cancer diagnosed between 1995 and 2010, and followed outcomes through 2016. Patients underwent primary cytoreductive surgery followed by platinum-based chemotherapy. Aspirin use was defined by medication documentation in two records more than six months apart. Statistical tests included Fisher's exact, Kaplan-Meier and Cox regression analyses. Seventy-seven patients met inclusion criteria. Fifty-four patients (70%) had stage I-II disease. Thirteen patients (17%) used aspirin. Aspirin users had a statistically longer disease-free survival compared to non-users (HR 0.13, p = .018). While median disease-free survival was not reached for either group, 1 of 13 (8%) aspirin users recurred at 24 months, compared to 18 of 64 (28%) non-users. Aspirin users demonstrated longer overall survival (HR 0.13, p = .015). Median survival was not reached for aspirin users, compared to 166 months for non-users. Aspirin use retained significance (HR 0.13, p = .044) after controlling for age, stage and cytoreductive status. In this small cohort of women with clear cell ovarian cancer, aspirin use correlated with improved disease-free and overall survival, and retained independent significance as a positive prognostic factor. Further research is warranted to confirm these findings before considering aspirin as a therapeutic intervention.
Keywords: Aspirin; Clear cell; Ovarian cancer; PIK3CA; Survival.