Use of menopausal hormone therapy before and after diagnosis and ovarian cancer survival—A prospective cohort study in Australia

Menopausal hormone therapy (MHT) use before ovarian cancer diagnosis has been associated with improved survival but whether the association varies by type and duration of use is inconclusive; data on MHT use after treatment, particularly the effect on health-related quality of life (HRQOL), are scarce. We investigated survival in women with ovarian cancer according to MHT use before and after diagnosis, and post-treatment MHT use and its association with HRQOL in a prospective nationwide cohort in Australia. We used Cox proportional hazards regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) and propensity scores to reduce confounding by indication. Among 690 women who were peri-/postmenopausal at diagnosis, pre-diagnosis MHT use was associated with a significant 26% improvement in ovarian cancer-specific survival; with a slightly stronger association for high-grade serous carcinoma (HGSC, HR = 0.69, 95%CI 0.54-0.87). The associations did not differ by recency or duration of use. Among women with HGSC who were pre-/perimenopausal or aged ≤55 years at diagnosis (n = 259), MHT use after treatment was not associated with a difference in survival (HR = 1.04, 95%CI 0.48-2.22). Compared to non-users, women who started MHT after treatment reported poorer overall HRQOL before starting MHT and this difference was still seen 1-3 months after starting MHT. In conclusion, pre-diagnosis MHT use was associated with improved survival, particularly in HGSC. Among women ≤55 years, use of MHT following treatment was not associated with poorer survival for HGSC. Further large-scale studies are needed to understand menopause-specific HRQOL issues in ovarian cancer.