Comparison of survival outcomes by adjuvant therapy modality for patients with high-risk endometrial carcinoma (469)

Abstract

<b>Objectives:</b> There are many approaches to adjuvant therapy for highrisk endometrial carcinoma, including chemotherapy (CT) only, radiation therapy (RT) only, combination "sandwich" therapy (ST: three cycles of CT, followed by RT, then completed with three additional cycles of CT), and other alternative combinations of CT and RT (MT: mixed therapy). The purpose of the study was to compare treatment outcomes for patients with high-risk endometrial carcinoma stratified by the modality of adjuvant therapy. <b>Methods:</b> This single-institution retrospective cohort study evaluated patients with high-risk endometrial carcinoma treated between 2015 and 2019. Following surgical staging, all patients underwent adjuvant therapy. We compared the outcomes of patients treated with ST to patients who received CT only, RT only, or MT. Outcomes included recurrence rate, site of recurrence, progression-free survival, and overall survival. We performed statistical comparisons with Chi-square analysis, Wilcoxon tests, and Fisher's Exact Test. Differences in survival were tested using log-rank tests. <b>Results:</b> Of the 123 evaluable patients, 33 (19.9%) received ST, 58 (33.1%) received CT only, 19 (11.5%) received RT only, and 13 (7.8%) received MT. Demographic, pathologic, and survival outcomes stratified by the modality of adjuvant therapy are described in Table 1. Despite having a more advanced disease (stage IIII/IV, ST: 31/33, 93.0% vs MT: 9/13, 69.2%), patients who received ST had a prolonged progression-free (ST: 20.21 ± 6.60 months vs MT: 8.12 ± 3.55, p=0.0224) and overall (0=0.002) survivals compared to patients who received MT. There were no significant differences in progression-free survival between patients who received ST and those who received CT only or RT only. There were also no significant differences in recurrence rate or site of recurrence between patients who received ST compared to other adjuvant therapy modalities. Patients who received CT only more frequently had stage IVB disease (22/58, 37.9%) than patients who received ST (1/33, 3.0%) and also experienced worse overall survival (p=0.002). There was no difference in overall survival between patients receiving ST compared to RT only. <b>Conclusions:</b> Patients with high-risk endometrial carcinoma treated with ST experienced prolonged progression-free and overall survivals compared to those treated with MT. Additional research is needed to further clarify the role of ST compared to alternative adjuvant treatments for high-risk endometrial carcinoma.