F. Fabi1, A. Akingbade2, R. Cartes3, J. M. G. Tsui3, and J. Alfieri3; 1Centre Hospitalier Universitaire de Québec, Québec, QC, Canada, 2Western University, London, ON, Canada, 3McGill University Health Center, Montréal, QC, Canada
Purpose/Objective(s): Serous endometrial carcinoma (SEC) is a high-risk histological subtype of endometrial neoplasia. The effectiveness of a variety of adjuvant therapies has previously been investigated in the treatment of such tumors, namely chemotherapy (CT), external beam radiotherapy (EBRT), and sequential chemotherapy and radiotherapy (CRT). However, optimal management of early-stage SEC still remains unclarified. In this study, we retrospectively evaluated the clinical outcomes, toxicities, and recurrence patterns of patients who underwent adjuvant treatment for early-stage SEC. Materials/Methods: We interrogated our institutional pathology database in order to retrospectively identify all cases of early stage SEC (stage I-II; FIGO 2009) treated from 2002 to 2019. Demographic data, pathological characteristics, adjuvant treatments, recurrence patterns, survival status as well as toxicity data were documented until September 2023. Overall Survival (OS) and Disease-Free Survival (DFS) were computed using Kaplan-Meier estimates and Cox’s Proportional Hazard model. Descriptive statistical analysis was used to report other data.
Results: 50 patients were identified. All of them underwent TAH+BSO and omentectomy, displaying mostly stage IA (60%), followed by IB (24%) and II (16%) disease. Median follow-up was 90.9 months (CRT group = 97.6 months, CT group = 28.3 months, RT group = 141.9 months). Most patients underwent adjuvant CRT (n=36, 72%), followed by CT (n=6, 12%), RT (n=6, 12%) and observation (n=2; excluded from analysis). 3-year OS and DFS were, respectively, 91% and 83% for CRT, 33% and 50% for CT, and 67% and 80% for RT. CRT had significantly better OS (HR 0.14, 95%CI 0.04-0.52, p<0.005) and DFS (HR 0.25, 95%CI 0.07-0.97, p=0.05) than CT alone. There were no significant OS or DFS benefits for RT when compared to CT or CRT. Recurrences were mostly distant (9 events; 8 CRT, 1 CT), followed by synchronous locoregional and distant relapse (3 events; 2 RT, 1 CRT). Locoregional recurrences were also observed (2 events; CT). Acute G3-4 toxicities were primarily hematologic (n=12, 8 CRT, 4 CT), followed by gastrointestinal (n=2, CRT) and genitourinary (n=1, CT). Late G3-4 toxicities were, similarly, chiefly hematologic (n=2, CRT) and genitourinary (n=1, CT).
Conclusion: Our data underlines the challenge of effectively treating early-stage SEC, as overall disease recurrence remains high despite adjuvant treatment. CRT appears to be superior to CT alone, but fails to demonstrate benefits when compared to RT. Considering that most recurrences were distant in nature, these results also highlight the necessity of developing better systemic therapeutic options.
