ESTRO 2025 - Abstract Book

S843

Clinical - Gynaecology

ESTRO 2025

2870

Poster Discussion PORTEC-3 protocol for high-risk endometrial cancer: Can we safely invert the therapeutic sequences? Ines Mlayeh 1,2 , Raouia Ben Amor 1,2 , Manel Limam 3 , Zeineb Naimi 1,2 , Ghada Bouguerra 1 , Rihab Haddad 1 , Awatef Hamdoun 1 , Lotfi Kochbati 1,2 1 Radiation Oncology, Abderrahmen Mami Hospital, Ariana, Tunisia. 2 Faculty of Medicine of Tunis, Tunis El Manar University, Tunis, Tunisia. 3 Epidemiology, Farhat Hached Hospital, Sousse, Tunisia Purpose/Objective: The PORTEC-3 protocol is the standard treatment for high-risk endometrial cancer (EC), but limited radiotherapy access in low-middle income countries (LMIC) leads to treatment delays. To address this issue, we reversed the PORTEC-3 sequence, starting with surgery, followed by chemotherapy (CT) and then radiotherapy (RT). This study aimed to evaluate loco-regional control, disease-free survival (DFS) local recurrence-free survival (LRFS), metastasis free survival (MFS) and overall survival (OS). Material/Methods: Between February 2018 and December 2023, we evaluated 52 high-risk endometrial cancer patients with a median age of 63 years. Of these, 36.5% had Type 2 EC, and 48.1% had high-grade tumors. Focal and extensive lymphovascular invasion (LVI) were seen in 32.7% and 34.6%, respectively. FIGO 2009 and 2018 stage distribution was: Stage IA (5.7%), IB (13.4%), II (9.6%), IIIA (15.4%), IIIB (1.9%), IIIC1 (30.8%), and IIIC2 (23.1%). All patients received four cycles of adjuvant chemotherapy (Taxol-carboplatin) followed by 45 Gy pelvic radiotherapy (25 fractions) with concurrent platinum-based chemotherapy. Survival analysis was performed using the Kaplan-Meier method, and prognostic factors were assessed through univariate and multivariate Cox regression. Results: Median follow-up was 31.4 months (range: 8.3-81.8). The recurrence rate was 19.2% (N=10): one with isolated pelvic lymph node recurrence, one with both vaginal recurrence and pulmonary metastasis, four with peritoneal carcinomatosis, and four with pulmonary metastasis. Five-year OS, DFS, LRFS, and MFS rates were 86.1%, 77.5%, 97.9%, and 79.3%, respectively.(Table1) Univariate analysis identified several significant prognostic factors for decreased OS, including obesity (p=0.006), aggressive histologic type (p=0.042), FIGO stage III (p=0.031), and neutropenia (p=0.003). For DFS, significant factors included obesity (p=0.017), smoking (p<0.001), aggressive histologic type (p=0.041), high grade (p=0.029), extensive lympho-vascular invasion (p=0.042), FIGO stage III (p=0.011), VMAT RT technique (p=0.045), more than two cycles of concomitant chemotherapy (p=0.004), and treatment delays(Table2). In multivariate analysis obesity ( HR=4.80; CI 0,64-15,2, p=0,018), delays between surgery and RT> 5 months(HR=4,49; CI: 0,77-16,11 p=0,02), and delays between surgery and CT> 10 weeks (HR=2,1; CI:1.056–4.187 p=0,034) were associated with decreased DFS but none of them had any impact on OS.