Potential competing risk of death in older high-risk endometrial carcinoma patients: Results from a multicentric retrospective cohort.

INTRODUCTION: Adjuvant therapeutic decisions in older endometrial carcinoma (EC) patients are challenged by a balance between more frequent aggressive EC and comorbidities. We assessed whether EC and comorbidities are competing or cumulative risks in older EC patients. METHODS: All consecutive patients treated for FIGO stage I-IV EC in two University Hospitals in Paris between 2010 and 2017 were retrospectively included. Patients were categorized as: <70 years (y), >70y without comorbidity (fit), and > 70y with a Charlson comorbidity index>3 (comorbid). Association between high-risk EC (2021-ESGO-ETRO-ESP) or comorbidity, and disease-specific-survival (DSS), was evaluated using Cox model (estimation of cause-specific hazard ratio (CSHR), and Fine-Gray model (subdistribution HR) to account for competing events (death unrelated with EC). RESULTS: Overall, 253 patients were included (median age = 67y, IQR[59-77], median follow-up = 61.5 months, [44.4-76.8]). Among them, 109 (43%) were categorized at high-risk (proportion independent of age), including 67 (26%) who had TP53-mutated tumors. Comorbidity and high-risk group were both associated with all-cause mortality (HR = 4.09, 95%CI[2.29; 7.32] and HR = 3.21, 95%CI [1.69; 6.09], respectively). By multivariate analysis, patients with high-risk EC exhibited poorer DSS, regardless of age/comorbidity (Adjusted-CSHR = 6.62, 95%CI[2.53;17.3]; adjusted-SHR = 6.62 95%CI[2.50;17.5]). Patients>70y-comorbid with high-risk EC had 5-years cumulative incidences of EC-related and EC-unrelated death of 29% and 19%, respectively. In patients <70y, 5-years cumulative incidence of EC-related and EC-unrelated death were 25% and < 1% (one event), respectively. CONCLUSION: High-risk EC patients are exposed to poorer DSS regardless of age/comorbidities, comorbidities and cancer being two cumulative rather than competing risks. Our results suggest that age/comorbidity alone should not lead to underestimate EC-specific survival.