ESTRO 2025 - Abstract Book

S868

Clinical - Gynaecology

ESTRO 2025

Purpose/Objective: Concurrent chemoradiotherapy followed by image-guided adaptive brachytherapy (IGABT) is the standard treatment for patients with locally advanced cervical cancer [1,2]. The purpose of this study is to describe the outcomes from two South American centers located in Argentina and Chile. Material/Methods: This retrospective cohort study includes patients with locally advanced cervical cancer treated with chemoradiotherapy between 2019 and 2023. This study was approved by the local ethic committees; data were obtained through the review of medical records and processed using STATA 18 (Statacorp LLC, USA), generating descriptive statistics and survival curves using the Kaplan-Meier method. Variable modeling was performed using Cox regression analysis. Results: 277 patients were included, with a median follow-up of 26.8 months (IQR 16.4-50.6). The median age was 46 years (IQR 37–58 years). Non-squamous histology accounted for 11.9% of cases. The stages distribution was: Stage I 14.1%; Stage II, 21.6%; and Stages III-IVa, 64.3%. 79.2% of patients received a median of 5 cycles of cisplatin (IQR 4 5). The median EQD2 with EBRT to the pelvis was 44.3 Gy (IQR: 44.3–46 Gy). The most common treatment regimens were 45 Gy delivered in 25 fractions, administered to 69.5% of the patients, and 50 Gy delivered in 25 fractions, administered to 25.3% of the patients. The cervical boost was predominantly delivered using HDR brachytherapy (97.8% of the patients). Additionally, 5 patients received EBRT boost and 1 patient was treated with LDR brachytherapy. Median total EQD2 to CTV HR was 83.9 Gy (IQR 83.6 - 86.5). Overall survival at 3 years was 78.8%: 94.6% for stage I, 83.5% for stage II, and 73.5% for stages III-IVA (Figure 1). Overall survival was analyzed considering stage, tumor size, non-squamous histology, ECOG, age, total treatment duration, and number of weekly cisplatin cycles. Hazard ratios (95% CI): stage II 2.18 (0.58-8.09); stage III-IV 3.18 (0.91-11.02); tumor size on physical examination 1.21 (0.96-1.52); non-squamous histology 0.79 (0.29-2.12); age 0.99 (0.97-1.02); ECOG 1 0.66 (0.32-1.34) - ECOG 2 1.36 (0.18-10.38); total treatment duration 1.02 (0.998-1.04); cisplatin cycles 0.73 (0.59-0.89).

Figure 1.- Overall survival by stage