Hormonal and Reproductive Risk Factors for Epithelial Ovarian Cancer by Tumor Aggressiveness

Background Approximately half of epithelial ovarian cancers are fatal within three years; however about 35% of women survive at least ten years. In the Nurses’ Health Study, New England Case-Control Study, Australian Ovarian Cancer Study, and NIH-AARP Diet and Health Study, we investigated potential differences in the associations with ovarian cancer risk factors by tumor aggressiveness, defined based on time from diagnosis until death. Methods We calculated relative risks (RR) and 95% confidence intervals (CI) for associations of known or suspected ovarian cancer risk factors with rapidly fatal (death within three years of diagnosis) and less aggressive tumors (all others) using Cox proportional hazards competing risks analysis (NHS, AARP) or polytomous logistic regression (NECC, AOCS). Results were combined using random effects meta-analysis. Results Increasing age was associated with greater risk of rapidly fatal versus less aggressive disease (OR, 5-yr increase: 1.39; 95% CI: 1.29–1.49 vs. OR: 1.09; 95% CI: 1.03–1.16, respectively; p-diff