ESTRO 2025 - Abstract Book

S252

Brachytherapy - Gynaecology

ESTRO 2025

and 3-year OS was 95% and 90% respectively. The incidence of Grade 2 or higher vaginal, bladder and rectal toxicities were 7.8 %, 4.8% and 4.8 % respectively.

Conclusion: Brachytherapy dose can be safely de-escalated in selected patients of LACC with limited HRCTV at brachytherapy. The results of the study are particularly relevant to resource constrained settings and can form the basis for the design of large randomised trials for brachytherapy dose de-escalation in the future.

Keywords: De- escalation, brachytherapy dose

References: 1 . Gupta A, Dey T, Rai B, et al: Point-Based Brachytherapy in Cervical Cancer With Limited Residual Disease: A Low- and Middle-Income Country Experience in the Era of Magnetic Resonance–Guided Adaptive Brachytherapy. JCO Glob Oncol 1602–1609, 2021 2 . Patel FD, Rai B, Mallick I, et al: High-dose-rate brachytherapy in uterine cervical carcinoma. Int J Radiat Oncol Biol Phys 62:125–130, 2005

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Digital Poster How to deal with needles: is there a right number of needles in interstitial brachytherapy for cervical cancer? Beatrice Anghel 1 , Anca Daniela Stanescu 2 1 Radiation Oncology, Sanador Oncology Center, Bucharest, Romania. 2 Obstetrics and Gynaecology, St. John Emergency Hospital, Bucur Maternity, Bucharest, Romania Purpose/Objective: Brachytherapy is an essential component of the treatment of locally advanced cervical cancer in addition to chemo radiation. When high volume disease and/or unfavorable topography is common, hybrid approach is needed and the addition of interstitial needles will provide an optimal therapeutic ratio. However, the right number of interstitial needles inserted can be a real challenge. We have examined our practice and we would like to share our learning curve as a recommendation in interstitial approach for cervical cancer analysing the number of needles used and in the same time maintaining the target coverage and protecting the normal structures. Material/Methods: 270 patients have been treated with interstitial brachytherapy between 2020-2024. The technique involves placement of transvaginal needles in addition to the tandem and ring under ultrasound imaging and planning is done through Computed Tomography (CT) imaging. Although the gold standard is magnetic resonance imaging (MRI), CT remains an acceptable solution when availability is a problem. The prescribed dose was 7Gy x4 or 8Gy x3, depending on the external beam radiotherapy dose in order to fulfill the GEC-ESTRO recommendations. The purpose of this study was to investigate possibilities for minimising the number of needles and to examine the impact of needle use reduction with the target volumes and the dosimetric results. Results: In the early days, when interstitial procedure was implemented, we started with 4 needles implants, then for 18 months we used an average of 10 needles which have met the requirements for target coverage and normal tissue dose parameters. Since 2022, an average number of 6 needles have covered the high risk volumes and simultaneously managed to reduce the dose to bladder, sigmoid and bowel below mandatory constraints. A