Adjuvant Radiotherapy Improves Overall Survival When Added to Surgery and Chemotherapy for Endometrial Carcinosarcoma: A Surveillance, Epidemiology, and End Results Analysis

Document Type

Article

Publication Date

11-1-2020

Publication Title

International Journal of Radiation Oncology Biology Physics

Abstract

Purpose/Objective(s) Endometrial carcinosarcoma (CS), or malignant mixed Mullerian tumor, is a high-grade variant of endometrial carcinoma with a high risk for recurrence. Adjuvant multi-agent chemotherapy (CHT) is a preferred treatment modality in all stages of disease, with or without radiotherapy (RT). As prospective data are lacking regarding the benefit of RT when added to adjuvant CHT in CS, we sought to analyze the Surveillance, Epidemiology, and End Results (SEER) database to ascertain whether RT improves overall survival (OS) and cancer-specific survival (CSS) when added to surgery and CHT for endometrial CS. Materials/Methods SEER 18 Custom Data registries (Nov 2018 submission) were queried for endometrial (ICD10 C54.1-9, C55.9) CS (ICD-0-3 8980-3). Patients with stage I-III CS who received CHT with or without RT were included for analysis. Univariate analysis (UVA) and multivariable analysis (MVA) using Kaplan-Meier and Cox proportional hazards regression modeling were performed. Propensity-score matched analysis with inverse probability of treatment weighting was performed to account for indication bias. Furthermore, conditional landmark analysis using a minimum follow-up time of 3 months was performed to minimize immortal time bias. Results A total of 1,541 patients treated from 1988-2016 were included in this analysis. Median age at diagnosis was 65 (IQR 59-71). Patients had FIGO stage IA (30%), IB (14%), II (9%), IIIA (8%), IIIB (3.6%), or IIIC (32%) disease. All patients received CHT and 54% received RT, either with external beam RT (EBRT) alone (25%), EBRT with a brachytherapy boost (9.7%), or brachytherapy alone (18.7%). On UVA, adjuvant RT improved OS (HR 0.65, 95% CI 0.56-0.77, p

Volume

108

Issue

3S

First Page

459

Last Page

459

DOI

10.1016/j.ijrobp.2020.07.2576

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