ESTRO 2025 - Abstract Book

Brachytherapy - Gastro-intestinal, paediatric brachytherapy, miscellaneous

S175

ESTRO 2025

149

Digital Poster Acute and late toxicity profile of liver interventional radiotherapy after direct (non-Seldinger) type of application - a single institution analysis. Mateusz Bilski 1,2,3 , Katarzyna Korab 4 , Julia Ponikowska 4 , Łukasz Kuncman 5,6 , Jacek Fijuth 6,5 , Paweł Cisek 1,2 1 Department of Brachytherapy, Saint John’s Cancer Center, Lublin, Poland. 2 Department of Radiotherapy, Medical University of Lublin, Lublin, Poland. 3 Department of Radiotherapy, Saint John’s Cancer Center, Lublin, Poland. 4 Department of Medical Physics, Saint John’s Cancer Center, Lublin, Poland. 5 Department of Radiotherapy, Medical University of Łódź, Łódź, Poland. 6 Department of External Beam Radiotherapy, Copernicus Memorial Hospital in Lodz Comprehensive Cancer Center and Traumatology, Łódź, Poland Purpose/Objective: Liver CT-guided brachytherapy in most centers involves application procedures performed by interventional radiologists using the so-called Seldinger method. There are centers where liver brachytherapy is performed only by radiation oncologists/ brachytherapists using direct, non-Seldinger methods of applications. Our study aimed to evaluate the acute and late toxicity profiles after liver direct, non-Seldinger, radiation- oncologist only, based applications. Material/Methods: Patients with the maximal number of 5 liver metastases were qualified for the analysis. All selected patients received general anesthesia. The radiation oncologist performed direct, non-Seldinger-based applications using 200 or 320-mm-long applicators. A 32-slice CT scanner with real-time fluoroscopic imaging was used. Single fractions of 15 Gy, 20 Gy, or 25 Gy were used. Patients were followed clinically and with serial imaging. Evaluation of acute (<6 months from brachytherapy) and late (>6 months from brachytherapy) toxicity profiles using Common Terminology Criteria for Adverse Events 4.0 was performed. Results: Overall, 270 patients were included, with 49.7 % of women (n=136), a median age of 65 years, and an ECOG ≤ 2 in all cases. The median total volume of liver metastases was 81 (1-1536) cc. A median of 2 (1-8) applicators was used. Doses of 15 Gy, 20 Gy, and 25 Gy were prescribed in 20 %, 35.16 %, and 44.81 % of patients, respectively. A median D2/3 in the uninvolved liver was 1.8 Gy (0.2-4.4). The most frequent G1/G2 acute side effect of brachytherapy was an increase in transaminases in 65 (24%) patients, followed by pain at the injection site in 54 (20%) patients. Additionally, 22 (8%) patients experienced nausea within one week following the procedure. Infections at the injection site occurred in 8 (3%) patients. An occurrence of significant G1/G2 bleeding necessitating red blood cell transfusion developed in 5 (2%) patients. All of these side effects were transient. Acute G3 complications, involving pain at the injection site and an increase in transaminases or total bilirubin, appeared in 8 (3%) patients and were resolved within the initial 3 months post-procedure with pharmacological treatment. No surgical intervention was required for the entire cohort. No late toxicity was reported during the follow-up period. Conclusion: The direct, non-Seldinger type of application for liver metastases, performed only by radiation oncologists, is safe. No> G2 acute or late toxicity was observed. This radiotherapy modality should be more frequently utilized in brachytherapy centers. Additional workshops for radiation oncologists should be planned to give them a broader techniques profile that can be used to treat liver metastases.

Keywords: brachytherapy, toxicity, liver metastases