Comparing survivals according to different adjuvant treatments in high-risk endometrial carcinoma: an international and propensity score matching study

Background: This study aimed to compare the effectiveness of different adjuvant therapies on oncological outcomes in high-risk endometrial cancer. Methods: A retrospective cohort study analysed data from two tertiary medical centres in Korea and Taiwan (01 January 2000 to31 December 2020). Patients with high-risk endometrial cancer who underwent debulking surgery were eligible for inclusion. Cohort 1 included patients with early stage-to-stage IIIC1disease who achieved complete surgical resection, while Cohort 2 comprised those with residual disease post-surgery or stage IIIC2/IV disease. Propensity score matching was performed. Results: Following propensity score matching, 110 and 70 patients were analysed in Cohorts 1 and 2, respectively. In cohort 1, progression-free survival (PFS) and overall survival (OS) did not differ significantly between patients treated with adjuvant radiotherapy alone and those receiving combined chemotherapy and radiotherapy (PFS hazard ratio (HR) 0.691, 95% confidence interval (CI) 0.360–1.324, p = 0.265; OS HR 0.953, 95% CI 0.375–2.423, p = 0.920). Subgroup analysis suggested a potential improvement in PFS with combination therapy among stage III patients (HR 0.362, 95% CI 0.129–1.015, p = 0.0534), although no OS differences were observed (HR 0.305, 95% CI 0.063–1.471, p = 0.139). In cohort 2, no significant differences were observed in PFS or OS between treatment groups (PFS adjusted HR (aHR) 1.435, 95% CI 0.725–2.841, p = 0.3; OS aHR 1.194, 95%CI 0.505–2.824, p = 0.687). Conclusions: Combined chemotherapy and radiotherapy may improve progression-free outcomes in patients with stage III high-risk endometrial cancer without residual disease post-surgery, compared to radiotherapy alone.