ESTRO 2025 - Abstract Book

S251

Brachytherapy - Gynaecology

ESTRO 2025

Conclusion: Weekly and biweekly interstitial and intracavitary brachytherapy are both safe and well-tolerated by patients. The choice of HDR fractionation schedule can be tailored to individual centers and patients. However, longer follow-up is needed to further evaluate clinical outcomes and long-term toxicity.

Keywords: cervix, brachytherapy, imaged-guided brachytherapy

References: 1. Hama Y, Uematsu M, Nagata I, Shioda A, Suda A, Sakurai Y, Kono M, Tamura T, Kusano S. Carcinoma of the uterine cervix: twice- versus once-weekly high-dose-rate brachytherapy. Radiology. 2001 Apr;219(1):207-12. doi: 10.1148/radiology.219.1.r01ap08207. PMID: 11274558. 2.Tharavichitkul E, Klunkin P, Lorvidhaya V, Sukthomya V, Chakrabhandu S, Pukanhaphan N, Chitapanarux I, Galalae R. The effects of two HDR brachytherapy schedules in locally advanced cervical cancer treated with concurrent chemoradiation: a study from Chiang Mai, Thailand. J Radiat Res. 2012;53(2):281-7. doi: 10.1269/jrr.11038. PMID: 22510600.

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Digital Poster Can Brachytherapy dose be safely de-escalated in selected patients of locally advanced cervical cancer in the era of IGABT? Bhavana Rai, Krishna Vamsi, Srinivasa GY, Satinder Kaur, Dharmendra Kumar Sah, Oinam Arun Singh, Sushmita Ghoshal Radiotherapy & Oncology, PGIMER, Chandigarh, India Purpose/Objective: The brachytherapy (BT) schedule of 7Gy x 4 fractions is commonly used after External beam chemo-radiation (CRT) to achieve an optimal combined HRCTV D90 dose >85Gy EQD2 in patients of locally advanced cervical cancer (LACC). Based on our institutional experience, a dose schedule of 9Gy x 2 fractions is still used in select patients with small HRCTV volumes, advanced age, severe co-morbidities and situations (eg COVID pandemic) necessitating abbreviated treatment In this study, we report the dosimetric and clinical outcomes of patients of LACC treated with 9Gy x 2 fractions schedule using image guided adaptive brachytherapy. Material/Methods: Patients of LACC treated with 9Gy x 2 fractions HDR brachytherapy, between year 2020- 2023 were analysed. The baseline and treatment related variables were recorded. Dosimetric variables such as HRCTV volume, Point A dose, HRCTV D90, D2cc of the Bladder, Rectum and Sigmoid were analysed . Descriptive data was generated for the study variables. Response assessment was done using RECIST 1.1 criteria with clinical examination and imaging when required. Toxicity was assessed using the CTCAE v5. Survival analysis was done with Kaplan Meir curves. Results: One hundred and three patients were included in the study. The median age was 56 years (Range – 34-77 years). A dose fractionation of 46 Gy over 4.5 weeks ( 2Gy per fraction)was most commonly used (80.6%) for external radiotherapy. Ninety patients (87.4%) had an MRI at diagnosis and all patients were treated with CT based adaptive brachytherapy. The median HRCTV volume was 23.4 cc (Range – 11.1 – 39.5 cc). The median Point A dose was 74.5 Gy (Range – 68.7-74.5 Gy) and the median HRCTV D90 dose was 83.96 Gy (Range – 75.07 – 101 Gy). The median D2cc of the bladder, rectum and sigmoid were 87.7 Gy (IQR – 82 – 91.9 Gy), 73.3 Gy (IQR – 65.03 – 85.04 Gy) and 68.3 Gy (IQR - 61.75- 74.8 Gy) respectively. After a median follow up of 31 months, the local control rate was 93.2%. The 2