ESTRO 2024 - Abstract Book

S271

Brachytherapy - Gynaecology

ESTRO 2024

In such cases, >15-20% of G3-4 late side effects can be expected, underscoring the need for high-risk consent and patient participation during shared decision making. In the future, standardized and prospective high-quality reporting based on the ESTRO/EORTC recommendations should be adopted (3). Patients requiring GRIB meet the criteria of type 1 re-irradiation. However, brachytherapy is characterized by high doses and steep gradients in the central pelvis, and relatively lower and more homogeneous doses towards the periphery. Therefore, subclassification of type 1 GRIB into type 1c for central, and type 1p for peripheral pelvic re-irradiation could be considered. The use of a common language will allow cross-center comparisons, improving our understanding of this field in the future.

Keywords: re-irradiation, recurrence, treatment reporting

References:

1. Sturdza A, Viswanathan AN, Erickson B, et al. American Brachytherapy Society working group report on the patterns of care and a literature review of reirradiation for gynecologic cancers. Brachytherapy 2020; 19:127-138.

2. Full list of references of this systematic review available at request to authors.

3. Andratschke N, Willman J, Appelt AL, et al. European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus on re-irradiation: definition, reporting, and clinical decision making. The Lancet Oncology 2022; 23: e469-e478

2474

Digital Poster

Factors affecting D90 HR-CTV of 3D image-based brachytherapy in locally advanced cervical cancer

Paramintra Chitmanee

Ratchaburi hospital, Radiation therapy and oncology center, Ratchaburi, Thailand

Purpose/Objective:

Intracavitary brachytherapy (IC) cover limited target volume but intracavitary and interstitial brachytherapy (IC/IS) can increase dose coverage to HR-CTV. There is no consensus guideline to select patients who need IC/IS brachytherapy. We study factors that are affecting for D90 HR-CTV dose to achieve GEC-ESTRO dose recommendations and also study clinical outcomes and toxicities for 3D image-based brachytherapy in our experiences.

Material/Methods:

A total of 424 patients with FIGO stage IB1 to IVA were treated with chemoradiation and high-dose-rate brachytherapy between 2014 and 2023. Computed tomography (CT) and/or magnetic resonance imaging (MRI) were done at baseline and before brachytherapy to plan implantation. The main applicators were Vienna-ring, Fletcher and Venezia applicators. Target delineation defined by the GEC-ESTRO guidelines with prescribed doses