S88
Brachytherapy - Gynaecology
ESTRO 2026
Conclusion: Definitive IGBT±EBRT yields oncological outcomes comparable to surgery with acceptable toxicity, representing a safe and effective curative option for medically inoperable early-stage EC. Given that a high proportion of surgically treated patients required adjuvant therapy, radiotherapy offers a less invasive and potentially better-tolerated approach without compromising efficacy. Keywords: endometrial cancer, brachytherapy , survival References: Rovirosa A, et al; Endometrial Task Group in the Gynecological Cancer Working Group; GEC-ESTRO Working Group. Exclusive 3D-brachytherapy as a good option for stage-I inoperable endometrial cancer: a retrospective analysis in the gynaecological cancer GEC-ESTRO Working Group. Clin Transl Oncol. 2022 Feb;24(2):254-265. Rovirosa Á, et al.; Endometrial Task Group. Stages I-III Inoperable Endometrial Carcinoma: A Retrospective Analysis by the Gynaecological Cancer GEC-ESTRO Working Group of Patients Treated with External Beam Irradiation and 3D-Image Guided Brachytherapy. Cancers (Basel). 2023 Sep 27;15(19):4750. Modeling urethral dose–toxicity relationship in image-guided brachytherapy for gynecological cancers: dosimetric assessment of genitourinary morbidity Tauseef Ali, Mahmoud Alfishawy, Swathi Bapani, Muhammad Ali Gurmani, Nirmal Kumar Babu, Mustafa Al Balushi, Ana Paula Galerani Lopes Radiation Oncology, University Medical City - Sultan Qaboos Comprehensive Cancer Care and Research Centre, Muscat, Oman Digital Poster 4965 Purpose/Objective: Image-guided brachytherapy (IGBT) has enabled precise dose delivery for gynecological malignancies, yet urethra remains an unstandardized organ in treatment planning. Although anatomically contiguous with high-dose regions, it’s largely overlooked, and its contribution to genitourinary (GU) morbidity is poorly characterized. Delineation of urethra is inconsistently performed, and the absence of validated constraints leads to potential underreporting of clinically meaningful doses. This study evaluates urethral dose parameters in gynecologic IGBT and explores potential correlations with GU toxicity. Material/Methods: A retrospective dosimetric analysis was conducted in 30 patients with gynecological malignancies treated with IGBT between October 2021 and August 2024. All
patients had CT and/or MRI-based planning with consistent urethral contouring from the bladder base to the introitus using a 1-cm brush diameter. Dosimetric endpoints included D0.1cc, D0.2cc, D0.5cc, and D1cc and were calculated and documented per fraction. Demographics, applicator type, and fractionation were documented. Early (<6 months) and late (>6 months) GU toxicities were graded using CTCAE v5.0. Results: Thirty patients (cervix: 67%, endometrium: 26%, vagina: 7%) totaling 99 image-sets were analyzed. Median age was 56 years (range 37–77). Ninety-three percent of patients received EBRT with VMAT and 73% received concomitant boost to involved nodes (52.5- 60Gy). Mean dose was 7.1 Gy/fraction (range 5–8 Gy) across an average of 3.3 fractions (range 2–5). Applicator distribution included single-channel (11.2%), multichannel (20.2%), ovoids/tandem (26.2%), and interstitial needles(42.4%). Urethral mean volume was 3.71 cc (2.6–7.7). Mean urethral dose metrics were: D0.1cc: 283.6 Gy (117–784.8 Gy), D0.2cc: 274.1 Gy (126.1–727.2Gy), D0.5cc 245.9 Gy (106-628.6 Gy) D1cc: 207.3 Gy (92.3–532.4 Gy). Acute grade 1–2 GU toxicity occurred in 8 patients (26%), while 2 patients (7%) developed late grade 3 toxicity (urethral stenosis and limiting urinary tract pain). Mean urethral doses were approximately threefold higher in those with grade 3 events. Conclusion: Our findings suggest a dose–response relationship between urethral irradiation and GU toxicity in gynecological brachytherapy. Although lower-grade events were not clearly dose-dependent, severe late toxicity correlated with higher localized doses. These results highlight the clinical relevance of the urethra as a functional OAR. Prospective validation in larger cohorts is warranted to establish urethral dose thresholds. Keywords: urethra dose, organ at risk, dosimetry Peri-operative complications in gynaecological brachytherapy – a tertiary centre experience La-Dantai Henriques 1 , Thanga H Sundaramoorthy 1 , Neha R Varghese 1 , Methushaa Suthanthirakumaran 1 , Tracey Lim Yew Fai 1 , Hannah Tharmalingam 1 , Peter Hoskin 1,2 , Mohammed Abdul-Latif 1 1 Department of Brachytherapy, Mount Vernon Cancer Centre, Northwood, United Kingdom. 2 Department of Cancer Sciences, University of Manchester, Manchester, United Kingdom Digital Poster 4992
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