Background: While menopausal hormone therapy (MHT) is an established endometrial cancer risk factor, its relationship with mortality among endometrial cancer patients is understudied.
Methods: Within the NIH-AARP Diet and Health Study, we examined the associations of pre-diagnosis MHT use with 10-year all-cause and endometrial cancer-specific mortality among 890 endometrial cancer patients. We used Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) adjusted for tumor characteristics, treatment, and other risk factors.
Results: Endometrial cancer cases were diagnosed a median of 4.6 years (range 0.0-10.1 years) after the second risk factor questionnaire was completed. We identified a total of 241 deaths, of which 104 were due to endometrial cancer. Compared with non-MHT use, pre-diagnosis use of estrogen plus progestin therapy (EPT)-only was associated with lower 10-year all-cause (HR 0.65, 95 % CI 0.43-0.99, based on 29 deaths) and endometrial cancer-specific mortality (HR 0.51, 95 % CI 0.26-0.98, based on 11 deaths). Recency of MHT use, assessed approximately 5 years prior to the endometrial cancer diagnosis, was associated with mortality. Compared with non-MHT users, former ET users had higher all-cause (HR 1.71, 95 % CI 1.02-2.88, based on 18 deaths) and endometrial cancer-specific mortality (HR 2.17, 95 % CI 0.96-4.90, based on 8 deaths), whereas current EPT users had nonsignificant lower risks of death.
Conclusion: Based on small numbers, we observed that pre-diagnosis use of EPT was related to lower mortality among endometrial cancer patients. Future studies examining the biological mechanisms underlying this association are warranted.