The Impact of Adjuvant Management Strategies on Outcomes in Women With Early Stage Uterine Serous Carcinoma.

Objective To determine the impact of different adjuvant strategies on outcomes in women with early-stage uterine serous carcinoma (USC). Methods Our retrospective database for women with endometrial carcinoma was queried for women with 2009 International Federation of Gynecology and Obstetrics (FIGO) stages I-II USC who underwent surgical staging between January 1991 and April 2019 followed by adjuvant management (observation, radiation therapy (RT), chemotherapy (CT), or combined modality treatment (CRT)). Chi-square tests were performed to compare differences in outcome by type of adjuvant management. Recurrence-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) were assessed by Kaplan-Meier and log-rank tests. Univariate and multivariate analyses (MVA) were performed to identify statistically significant predictors of survival endpoints. Results We identified 171 women who met our inclusion criteria. The median follow-up time was 70.5 months. Seventy-five percent of the study cohort was FIGO stage IA, 13% were stage IB, and 12% were stage II. All women underwent pelvic lymph node dissection with a median number of dissected lymph nodes of 14. Omentectomy was performed in 64% of patients. Adjuvant RT was utilized in 56% of women (65 patients received vaginal brachytherapy alone, 10 patients received pelvic RT, and 21 patients received a combination of both). The most commonly used chemotherapy regimen was carboplatin and paclitaxel with a median number of cycles of six. A total of 44% of the cohort received CRT, 12% received RT alone, 19% received chemo alone, and 25% were observed. Five-year RFS was 73% for those who received CRT, 84% for those who received RT alone, 68% for those who received CT alone, and 55% for those who were observed (p=0.13). Five-year DSS was 81%, 94%, 71%, and 60%, respectively (p=0.02). Five-year OS was 76%, 70%, 60%, and 56%, respectively (p=0.11). On MVA of OS and DSS, a higher percentage of myometrial invasion, the presence of lower uterine segment involvement, positive peritoneal cytology, and receipt of chemotherapy alone/observation were independent predictors of worse outcomes. The sole independent predictor of worse RFS on MVA was the presence of positive peritoneal cytology. Conclusion In this cohort of women with early-stage USC who underwent surgical staging, adjuvant radiation treatment with or without chemotherapy was associated with improved survival endpoints and trended toward improved recurrence rates.