Introduction This study aims to compare survival outcomes of various adjuvant treatments for high-risk endometrial cancer, including pelvic radiotherapy, chemotherapy, and combined chemotherapy and radiotherapy since there is limited research available that compares their outcomes.

Methods This retrospective cohort study used data between January 1, 2000, and December 31, 2020 at two tertiary centers in Korea and Taiwan. Adjuvant therapy was divided into 3 categories: systemic chemotherapy, radiotherapy, and combination of chemotherapy and radiotherapy. Propensity score matching was done based on the stage and cell type.

Results After removing patients with incomplete data from a total of 626 patients with high-risk endometrial cancer, 519 patients were included in the study. Among these, 176 received radiotherapy, 200 received chemotherapy, and 143 received a combination of radiotherapy and chemotherapy. After matching patients using propensity scores, 83 patients were included in each treatment group for analysis. There was no significant difference in survival between groups when all patients, early stage patients (stage I-II), and advanced stage patients (stage III-IV) were considered. Although statistical significance was not reached after matching, advanced stage patients had a higher survival rate when treated with combined chemotherapy and radiotherapy. Further analysis of the combined treatment by dividing it into different methods did not reveal any differences in survival.

Conclusion/Implications There was no significant variation in the survival benefits among the different stages and treatment categories. However, for stage III and IV groups, the combination of radiotherapy and chemotherapy is believed to offer an advantage in terms of survival.