Long-term Patterns of Excess Mortality among Endometrial Cancer Survivors

Background: We investigated excess mortality after endometrial cancer using conditional relative survival estimates and standardized mortality ratios (SMR). Methods: Women diagnosed with endometrial cancer during 2000-2017 (N = 183,153) were identified in the Surveillance Epidemiology and End Results database. SMRs were calculated as observed deaths among endometrial cancer survivors over expected deaths among demographically similar women in the general U.S. population. Five-year relative survival was estimated at diagnosis and each additional year survived up to 12 years post-diagnosis, conditional on survival up to that year. Results: For the full cohort, 5-year relative survival was 87.7%, 96.2%, and 97.1% at 1, 5, and 10 years post-diagnosis, respectively. Conditional 5-year relative survival first exceeded 95%, reflecting minimal excess mortality compared with the general population, at 4 years post-diagnosis overall. However, in sub- group analyses, conditional relative survival remained lower for Black women (vs. White) and for those with regional/distant stage disease (vs. localized) throughout the study period. The overall SMR for all-cause mortality decreased from 5.90 [95% confidence interval (CI), 5.81-5.99] in the first year after diagnosis to 1.16 (95% CI, 1.13-1.19) at 10+ years; SMRs were consistently higher for non-White women and for those with higher stage or grade disease. Conclusions: Overall, endometrial cancer survivors had only a small survival deficit beyond 4 years post-diagnosis. However, excess mortality was greater in magnitude and persisted longer into survivorship for Black women and for those with more advanced disease. Impact: Strategies to mitigate disparities in mortality after endometrial cancer will be needed as the number of survivors continues to increase.