Adjuvant Therapy in Early Uterine Serous Carcinoma (324)

Objectives: Uterine serous carcinomas represent approximately 10% of all endometrial cancers but are responsible for nearly 40% of all endometrial cancer-related deaths. Given the relatively low incidence of this disease, there are limited prospective data to guide adjuvant treatment decisions in early-stage disease. The purpose of this study was to evaluate the impact of adjuvant therapy on recurrence-free and overall survival in women with stage I-II pure uterine serous carcinoma. Methods: IRB approval was obtained. Using an institutional pathology database, we retrospectively identified all patients with 2009 FIGO stage I and II pure uterine serous carcinoma treated at a single institution from January 2006 to December 2019. Demographic, clinical-pathologic, treatment, and outcome data were collected using the electronic medical record. Serous histology was confirmed by a gynecologic pathologist, and only cases of pure uterine serous histology were included. Data were compared using descriptive statistics. Survival analyses were performed using Kaplan-Meier and Cox proportional hazard methods. Results: Ninety-four patients meeting inclusion criteria were identified with a median follow-up time of 33.5 months. The median age was 68 years (range: 49-87), the majority of patients were White (n=78, 83.0%), and the median BMI was 30.7 (range: 14.2-57.3). The minimally-invasive surgical staging was performed in 59.6% of cases (n=56). Most patients had stage IA disease (n=70, 74.5%), and lymphadenectomy was performed in 90.4% of cases (n=85). Most patients (n=79, 84.0%) received adjuvant therapy, and a majority of patients received a combination of systemic chemotherapy and radiation therapy (n=55, 58.5%), with the most common combination being chemotherapy plus vaginal brachytherapy (n=42, 44.7%). Most patients (n=77, 81.9%) remained without evidence of recurrent disease at the most recent follow-up, while 17 patients (18.1%) had experienced recurrence. Patients who received six cycles of adjuvant chemotherapy experienced improved overall survival (p=0.004) and improved recurrence-free survival (p=0.02) compared to those who received no adjuvant chemotherapy. Conclusions: Patients with surgically staged early pure serous uterine carcinoma who received six cycles of adjuvant chemotherapy had significantly improved overall and recurrence-free survival compared to those who did not receive adjuvant chemotherapy.