Survival for endometrial cancer as a second primary malignancy.

Abstract

BackgroundEndometrial cancer (EC) often occurs subsequently to a primary cancer arising from a different site. However, little is known regarding the survival experience of EC as a second primary (ECSP) malignancy, specifically in relation to the original primary site and prior treatment.MethodsUsing Florida's cancer registry, all EC cases (first, second, or higher‐order) diagnosed from 2005–2016 were analyzed. Kaplan–Meier methods and Cox Regression were used in a cause‐specific survival analysis.ResultsA total of 2879 clinically independent ECSPs and 42,714 first primary ECs were analyzed. The most common first primary sites for ECSPs were breast cancer (BC) (n = 1422) and colorectal cancer (CRC) (n = 359). Five‐year cause‐specific survival was 84.0% (95% CI: 83.6–84.3) for first primary ECs and 81.8% (95% CI: 80.0–83.4) for ECSPs. After adjusting for age, race/ethnicity, histology, and stage at diagnosis, ECSPs had a lower risk of EC mortality than first primary ECs (hazard ratios [HR] 0.88, 95% CI: 0.79–0.97). ECSPs with a first primary CRC had a higher risk of EC‐specific death (HR 1.47, 95% CI: 1.04–2.06) compared to ECSPs that followed BC in multivariable analysis. Finally, women who had chemotherapy for ECSP and preceding BC did not have a higher risk of death (HR 0.80, 95% CI: 0.49–1.31) compared to those who only received chemotherapy for first primary EC.ConclusionsECSPs present a complex clinical profile. ECSP survival is superior to that of first primary EC. However, ECSPs following CRC may constitute a population of interest for their worse prognosis. Chemotherapy for a previous BC does not seem to impact the effectiveness of chemotherapy for ECs.