Treatment Outcomes and Toxicity Profiles with PORTEC-3 Trial Regimen in South Asian Cohort of High-Risk Endometrial Cancer Patients: A Single-Center Ambispective Analysis.

Objectives: Adjuvant chemoradiation followed by chemotherapy is the current standard of care in high-risk endometrial cancer after the PORTEC-3 trial. There is a lack of data on this treatment regimen in the South Asian patient cohort. The present study aims to assess toxicity profiles and outcomes in this cohort of patients. Materials and Methods: High-risk endometrial cancer patients planned for adjuvant chemoradiation followed by chemotherapy were included. Toxicity was graded using the Radiation Therapy Oncology Group and Common Terminology Criteria for Adverse Events criteria. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Survival curves were compared using the log-rank test. Cox regression analysis was done to find out the predictors of DFS. Results: This study included 58 patients treated from October 2016 to August 2022. Median age was 61 years (interquartile range [IQR] 56-66), with Fédération Internationale de Gynécologie et d'Obstétrique Stages I = 26 (44.8%), II = 5 (8.6%), and III = 27 (46.6%). p53 positivity was seen in 38 (65.5%) patients. Intensity-modulated radiotherapy was used in 44 (79.3%) patients. There was no treatment discontinuation during chemoradiation. Acute Grade 2 and above toxicity during chemoradiation were diarrhea in 10 (17.2%) and hematological in 2 (3.4%). For the planned adjuvant chemotherapy in 55 patients, 51 (92.7%) completed four cycles. Grade 2 or above neuropathy was seen in 11 (20%), with 5 (9%) having persisting neuropathy at 1-year follow-up. At a median follow-up of 31 months, 15 (25.8%) patients recurred; distant = 13 and isolated para-aortic = 2. The median time to recurrence was 16 months (IQR 12-22), with 80% (12 out of 15) of recurrence within the first 2 years of follow-up. The actuarial 5-year DFS and OS were 63.8 and 76.5%, respectively. In univariate analysis, p53 positivity and lymphovascular space invasion were predictors for DFS, with p -values 0.031 and 0.027, respectively. There was no significant predictor identified in multivariate analysis. Conclusion: There is good tolerance and compliance to adjuvant chemoradiation and chemotherapy in this South Asian cohort of patients with high-risk endometrial cancer, with no toxicity-related treatment breaks during radiation. The majority of the recurrences were seen at distant sites and within the first 2 years of follow-up. These findings are in line with the outcomes of the PORTEC-3 trial.