ESTRO 2025 - Abstract Book

S871

Clinical - Gynaecology

ESTRO 2025

4101

Poster Discussion Outcomes of Chemoradiation in Cervical Cancer: A Pooled Data from Single-Center Two Prospective Trials between “EMBRACE II” and “HYPOCx-iRex” study Tissana Prasartseree, Pittaya Dankulchai, Wiwatchai Sittiwong, Pichayut Nakkrasae, Nardlada Viboonmongkol, Supamon Nitipitch, Suchada Junlabut Division of Radiation Oncology, Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand Purpose/Objective: The purpose of this study was to evaluate the oncologic outcomes of chemoradiation in cervical cancer by pooling data from two single-center prospective trials, "EMBRACE II" and "HYPOCx-iRex." By combining results from these trials, this analysis aims to provide a comprehensive assessment of treatment efficacy, including local control, survival rates, and recurrence patterns. Material/Methods: This is a pooled analysis of 68 patients from two single-center prospective trials, "EMBRACE II" (N=28) and "HYPOCx iRex" including conventional radiotherapy (CVRT) (N=19) with 45Gy/25F, and hypofractionated radiotherapy (HYPO, N=21) with 44Gy/20F evaluating the oncologic outcomes of chemoradiation in cervical cancer patients. Clinical outcomes, including local control, pelvic. paraaortic, nodal, locoregional, and distant metastatic control (LC, PVC, PAC, NC, LRC, DMC), event-free and overall survival (EFS, OS) were collected. Kaplan-Meier analysis, were performed to assess the impact of treatment variables on oncologic outcomes. Results: The median follow-up for HYPO were 24 months (IQR: 19-29), CVRT at 23 months (17-32), and EMBRACE-II at 38 months (24.5-43). There were no significant differences in age across the groups (p = 0.72), with a median age of 52 years for HYPO and EMBRACE-II, and 58 years for CVRT. Most patients were staged as IIB or IIIC1. There were no significant differences in staging across the groups (p = 0.8). Squamous cell carcinoma was the most common histology across all groups, with no significant difference between the groups (p = 0.88). HYPO had the shortest overall treatment time, overall EBRT time, and time to brachytherapy (OTT/OERT/TBT) with median of 39/33/27 days, while CVRT were 47/43/30 days and EMBRACE-II 45/43/30 days (p < 0.001). D90 HR-CTV achieved 90 Gy EQD2,10 in every arms. At the 2-year follow-up, no significant differences were observed between the groups across most outcomes, especially LC, DMC, and EFS. A trend of higher PVC, PAC, NC, and LRC was observed in HYPO arm but no statistical significance, corresponding to the trend in the patterns of failure. Notably, the PAC data for the HYPO group showed a lack of failure. Similarly, the 18-month follow-up revealed higher gastrointestinal (GI ≥2, GI ≥3) toxicity in HYPO without statistical significance, and no significant differences for genitourinary (GU ≥2) conditions.