International Federation of Gynecology and Obstetrics 2023 stage IIIB2 endometrial cancer with pelvic peritoneal metastasis: assessment of adjuvant therapy effect on survival.

The 2023 International Federation of Gynecology and Obstetrics (FIGO) endometrial cancer staging schema classifies pelvic peritoneum only metastasis as stage IIIB2 disease. In this retrospective cohort study of 193 patients with FIGO 2023 stage IIIB2 endometrial cancer who underwent primary hysterectomy from 2006 to 2015 identified in the Commission-on-Cancer's National Cancer Database, systemic chemotherapy without external beam radiotherapy was the most frequent adjuvant therapy type (48.7%), followed by combination systemic chemotherapy and external beam radiotherapy (42.0%) and external beam radiotherapy without systemic chemotherapy (9.3%). After controlling for patient age, race and ethnicity, co-morbidity, and histology, combination systemic chemotherapy and external beam radiotherapy was associated with 40% reduction of all-cause mortality compared with systemic chemotherapy without external beam radiotherapy (5-year rates: 63.1% vs 45.7%, adjusted-hazard ratio 0.60, 95% confidence interval 0.40-0.92). This reduction of all-cause mortality for combination systemic chemotherapy and external beam radiotherapy compared with systemic chemotherapy without external beam radiotherapy increased to 55% among non-endometrioid histology (5-year overall survival rates: 52.0% vs 33.4%, adjusted-hazard ratio 0.45, 95% confidence interval 0.23-0.88). In conclusion, the results of this investigation suggest that, despite peritoneal disease spread, multi-modal treatment with combination systemic and local therapies may improve survival in FIGO 2023 stage IIIB2 endometrial cancer, especially in non-endometrioid histology.