ESTRO 2025 - Abstract Book

S210

Brachytherapy - Gynaecology

ESTRO 2025

394

Digital Poster Feasibility and clinical results of brachytherapy for cervical cancer with distal parametrial involvement: experience of a French institute Camille Roukoz 1 , Laurence Bauwens 1 , Benoît Alignet 1,2 , Salvatore Cozzi 1 , Frederic Lafay 3 , Amina Lazrek 1,4 , Magali Sandt 3 , Yasmine El Houat 1 , Frederic Gassa 3 , Anne-Agathe Serre 1 1 Radiotherapy, Centre Léon Bérard, Lyon, France. 2 Université Claude Bernard Lyon 1, Inserm, Lyon, France. 3 Physics, Centre Léon Bérard, Lyon, France. 4 Radiotherapy, International University Hospital Cheikh Zaid, Rabat, Morocco Purpose/Objective: Brachytherapy (BT) is challenging for locally advanced cervical cancer (LACC) with distal parametrial (DP), vaginal, and/or nearby organ involvement. Our study evaluates the feasibility and efficacy on cases of DP involvement, using the Venezia® applicator offering the possibility of implanting DP with oblique and/or transperineal needles. Material/Methods: This retrospective cohort study included, from December 2017 to September 2022, patients treated for LACC with PD involvement by radiochemotherapy (RCT) followed by BT. A clinical examination and magnetic resonance imaging (MRI) were performed before and after RCT. The Venezia® applicator was used. We report clinical outcomes and dosimetric data. Results: Among 51 patients included, 37.3% were FIGO2018 stage IVA, 19.6% stage IIIC2, 27.5% stage IIIC1, 7.8% stage IIIB, 3.9% stage IIB and 4% stage IVB (single metastasis). Proximal parametrial involvement was present in 98%, and 49% had bilateral DP involvement. Ureterohydronephrosis was present in 45.1% of patients unilaterally, 21.6% bilaterally and absent in 33.3%. Pelvic wall was affected bilaterally in 17.6% and unilaterally in 3.9%. After RCT, 5.9% of patients had a complete response. DP involvement persisted in 52.9% of patients unilaterally and 11.8% bilaterally. Regarding BT, the mean number of activated needles was 5.2 (1; 8) for straight, 2.3 (0; 7) for oblique, and 1.3 (0; 8) for transperineal. The mean D90 in EQD2 was 83.4Gy (58.3, 89.4) for CTV-HR and 67.9Gy (44.3; 78.1) for CTV-IR. The mean D2cc, in EQD2, for the rectum was 62.9Gy (9.9; 76.0), 61.4Gy (46.2; 75.2) for the sigmoid, 73.8Gy (55.7; 92.6) for the bladder and 59.1Gy (46, 78.5) for the intestines. The mean follow-up was 20.8 months (15.41; 36.44). At 3 months, 62.7% had a complete local response (image), 21.6% had a partial response and 738% had local progression. Metastatic progression occurred in 25.5%. Six patients (11.8%) underwent closure surgery, with residual tumor in 66.7%. At one year, 57.5% of patients had no recurrence and 41.9% at two years. Overall survival at 1 year was 89.7% and 66.6% at 2 years. Disease-free survival was 17.3 months and overall survival was 38.1 months.