ESTRO 2025 - Abstract Book

S787

Clinical - Gynaecology

ESTRO 2025

The aims of this study were to study preliminary results and toxicity with these new techniques and then to compare it to previous techniques.

Material/Methods: This is a retrospective study including patients with LA-CC treated with CCR with IMRT (Median dose: 50.4 Gy [45 64]) and HDR BT (2 or 3 fractions of 7 Gy) between September 2021 and December 2023. Their results were compared with results of 151 patients treated in our department between 1993 and 2012 with 2-3D CCR and low dose rate BT. Results: Fifty-two patients were included. Tumors were classified as stages IIB-IVA in 42 cases (80.7%). Nodal-boost up to 60 64 Gy was delivered to 11 patients (21.15%). Median treatment duration was 61 days [49-182]. First evaluation showed a complete response in 27 cases (52%) and partial response in 22 cases (42.3%). Nineteen patients (36.5%) underwent closing surgery, and 12 histologic complete responses (63.1%) were found. A residual tumor was found in 7 patients, with a median tumor size of 0.6 cm [0.2-6]. After a median follow-up of 26 months [9-40], 2 year-overall survival (OS), locoregional relapse-free survival (LRRFS), metastasis-free survival (MFS) and event-free survival (EFS) were 84.2%, 89.3%, 72.5% and 71.9%, respectively. Treatment tolerance was excellent with only grade 1 acute (9.6%) and late toxicities (13.5%). Stage IIB-IV was associated with worse OS (p=0.05), EFS (p=0.043) and MFS (p=0.046). Distal parametrial extension was associated with a worse LRRFS (p=0.001). A number of chemotherapy concomitant cures > 3 was associated with better MFS (p=0.021) and EFS (p=0.047). Complete response to treatment was associated with better OS (p=0.015), EFS (p=0.02), LRRFS (p=0.021) and MFS (p=0.006). In our older series, 2 year-OS, LRRFS, MFS and EFS were respectively 65.1%, 72.4%, 64% and 52.7%. Grade 3 toxicity was reported in 6,3% of cases.