External Beam Versus Brachytherapy as Adjuvant Radiation Therapy Modality in Patients with Stage II Endometrial Cancer: A Single Institution Experience

Abstract

Current NCCN guidelines allow for the physician to choose between EBRT, brachytherapy, or a combination of both to treat FIGO stage II endometrial cancer. Physicians will typically choose the type of treatment based off of other risk factors such as grade, histology, size, depth of myometrial invasion, age, and presence of lymphovascular invasion. Henry Ford has a large database of patients who have been treated for endometrial cancer with adjuvant radiation following surgery and we sought to use this database to explore this area. To determine the impact of adjuvant radiation treatment (RT) modality on overall survival (OS), recurrence-free survival (RFS), and disease-specific survival (DSS) in patients with FIGO stage II uterine endometrioid carcinoma (EC). Our prospectively-maintained database was quired for women with stage II uterine EC who underwent hysterectomy between 1990 and 2018. 100 patients were identified. None received adjuvant chemotherapy. OS, RFS, DSS were all calculated from the date of surgery by use of Kaplan-Meier analysis. Cox regression analysis was used to examine risks associated with changes in OS, RFS, or DSS. The median follow-up time for the study cohort was 110.6 months, and the median age was 66 years. Lymphadenectomy was performed in 78%, peritoneal cytology in 85%. On pathology, 42% of patients were grade 1, 39% grade 2, and 19% grade 3. Adjuvant treatment was external beam radiation therapy (EBRT) alone in 15% of patients, HDR vaginal cuff brachytherapy (BT) alone in in 29% and both in 56% of patients. 5-year RFS for the study cohort was 77%, DSS was and OS was 70%. On multivariate analysis grade 3 vs 1 was a significant predictor for OS (HR 3.11, p 0.0228), RFS (HR 5.1, p 0.0333), but not DSS (HR 6.06, p 0.12). Radiation treatment modality (EBRT, BT, or both) were not found to be significant predictors for any of survival endpoint. In our group of stage II endometrial cancer patients adjuvant RT modality was not predictive of OS, RFS, or DSS. The only independent significant predictor in this group was grade 3 vs 1, and this was only significant for OS and RFS.