ESTRO 2025 - Abstract Book

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Brachytherapy - Urology

ESTRO 2025

Conclusion: This study confirms, in one of the largest cohorts worldwide, with ultralong-term follow-up, that LDR-BT as monotherapy is an effective treatment for low- and intermediate-risk prostate cancer with longterm tumor control and excellent acute and late GU and GI toxicity profiles.

Keywords: Prostate cancer, brachytherapy, LDR

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Digital Poster Multimodal therapy for synchronous rectal and prostate cancer using EBRT and HDR brachytherapy as a boost. Michał Kurzyński, Maciej Fortuna, Agata Romaniszyn, Roksana Kudzia, Damian Nahajowski, Marcin Hetnał Amethyst Radiotherapy Centre, Ludwik Rydygier Memorial Hospital, Krakow, Poland Purpose/Objective: This study aimed to evaluate the efficacy and safety of a curative treatment regimen combining External Beam Radiotherapy (EBRT), High-Dose-Rate (HDR) brachytherapy as a boost and anterior rectal resection for managing synchronous rectal and prostate cancers. The goal was to assess disease control outcomes and toxicity levels in a cohort of patients receiving this multimodal approach. Material/Methods: Four patients, aged between 63 and 78, diagnosed with synchronous rectal and prostate cancer were treated with a multimodal regimen. The treatment protocol included EBRT with chemotherapy (5FU-LV or capecitabine), combined with HDR brachytherapy boost doses ranging from 12 to 13.5 Gy. Eight weeks after this neoadjuvant therapy, the patients underwent sphincter-sparing surgery with total mesorectal excision. In addition, three patients out of four were qualified to long-term androgen deprivation therapy (ADT). Cancer staging for rectal cancer varied from cT3N1b to cT4aN2a, and prostate cancer TNM categories were between cT2a-2c, ranging from Gleason scores of 3+3 to 4+4. Results: The follow-up period was between 6-90 months (mean 46,5 months), all without evidence of recurrence of any malignancy. The treatment was well-tolerated by patients, reporting only G1 low-grade urinary symptoms, with no high-grade toxicities observed. The combined therapy achieved favorable local control outcomes across the cohort. The therapeutic approach effectively managed disease progression, showing promise for use in such cases with two synchronous malignancies. Conclusion: The study suggests that HDR brachytherapy as a boost to EBRT is a feasible and effective approach for treating synchronous rectal and prostate cancers. HDR brachytherapy as a boost following EBRT appears to provide targeted, higher radiation doses that enhance tumor control while reducing toxicity to surrounding tissues. Further studies with a larger number of patients are warranted to confirm these findings. To our knowledge, this is the largest case series of synchronous rectal and prostate cancers treated with EBRT combined with HDR brachytherapy of the prostate.

Keywords: prostate cancer, rectal cancer, HDR brachytherapy

References: 1. Konat-Bąska K et al, Interstitial high-dose-rate brachytherapy as a boost in synchronous prostate and rectal cancer treatment: case report and literature review. J of Contem Brachytherapy. 2020;12(2):181-187