Adjuvant vaginal brachytherapy and chemotherapy versus pelvic radiotherapy in early-stage endometrial cancer: Outcomes by risk factors.

OBJECTIVE: To report on patterns of care as well as evaluate the two treatment regimens using a large retrospective hospital-based registry to identify possible subgroups of patients who may experience benefit with VBT + CT vs. EBRT. METHODS: Patients from the National Cancer Database (NCDB) were identified who met the inclusion criteria for GOG 249 and were treated with either VBT + CT or WPRT. Demographic, clinicopathologic, and treatment factors were collected. Association of treatment type and other variables with overall survival was analyzed using Cox proportional hazards model. Subset analyses were performed based on a variety of risk factors, including high risk pathologies, surgical nodal sampling, and grade. RESULTS: A total of 4,602 patients were included in the analysis, with 41% receiving VBT + CT and 59% receiving WPRT. For the entire cohort, VBT + CT was associated with improved survival, with 3-year overall survival 89.6% vs. 87.8% (hazard ratio 1.24, 95%CI 1.01-1.52, p = 0.04). On subset analysis, patients with serous histology experienced benefit with VBT + CT, while high-grade endometrial patients without lymph node dissection experienced improved survival associated with EBRT. After exclusion of serous histology, there was no survival difference associated with treatment type. CONCLUSIONS: VBT + CT was associated with superior survival outcomes in patients with early-stage serous carcinoma. For non-serous histology, treatment modality was not associated with a difference in survival, although patients with high-grade disease and no nodal dissection experienced benefit from EBRT.