S177
Brachytherapy - Urology
ESTRO 2026
were observed at 3 years. Majority of acute and late genitourinary (GU) and gastrointestional (GI) toxicities were grade 1, with acute toxicities largely resolving by 3-month follow-up. The most common late grade >2 toxicities were weak stream and diarrhea, representing 6.7% and 8.3% of GU and GI toxicities respectively at 1-year follow-up. Neither the use of rectal spacer nor pelvic nodal irradiation were associated with differences in GI toxicity rates. With minimal clinically important difference (MCID) defined as 5.0 points, there was a clinically meaningful worsening of -7.7 points (p<0.001) in EPIC urinary scores from baseline to 1-month follow-up and a subsequent improvement of 5.0 points (p<0.001) from baseline to 3-year follow-up. Conclusion: Focal MRgHDR brachytherapy combined with SBRT demonstrated a favourable therapeutic index with high biochemical control rates and low incidence of late toxicity. Consistently, patient-reported quality-of- life reverted to baseline levels after a mild transient impact. Further studies on this combinatorial approach seem warranted to maximize the benefit of brachytherapy boost for selected patients with localized prostate cancer. Keywords: MR-guided HDR brachytherapy, focal boost, prostate Ten-year outcomes after single-fraction HDR brachytherapy boost plus EBRT for localized prostate cancer. Kanta KA, Youssef Ougaddoum, Mario Terlizzi, Lucie Calmels, Vithun Anthonipillai, Alberto Bossi, Pauline Maury, Pierre Blanchard Radiotherapy, Gustave Roussy Institute, Villejuif, France Purpose/Objective: To evaluate long-term biochemical and metastasis- free outcomes, toxicity, and potential dosimetric predictors in patients treated with a single-fraction high-dose-rate (HDR) brachytherapy boost combined with external beam radiotherapy (EBRT) for localized prostate cancer. Material/Methods: Between 2015 and 2023, 333 patients were treated with a single-fraction HDR boost using Iridium-192, followed by EBRT. RT was delivered with intensity- modulated radiotherapy, 3D conformal and stereotactic techniques. Clinical and dosimetric parameters, including NCCN risk group (intermediate, high, very high), androgen deprivation therapy (none, ≤ 6 months, >6 months), and dosimetric metrics (<15 Gy vs ≥ 15 Gy, EQD2 < 110 Gy vs ≥ 110 Gy, D90 < 100 % Digital Poster Highlight 4973
dose rate (HDR) brachytherapy for localized prostate cancer: Does dose heterogeneity matter? Radiother Oncol J Eur Soc Ther Radiol Oncol. 2022;169:51-56. doi:10.1016/j.radonc.2022.02.007
Digital Poster Highlight 4702 Focal MR-Guided HDR Brachytherapy Boost Combined with SBRT for Localized Prostate Cancer Ege Babadagli 1 , Carlton Johnny 2 , Anna Theresa Santiago 3 , Rachel Glicksman 1 , Aruz Mesci 1 , Srinivas Raman 4 , Joelle Helou 5 , Andrew McPartlin 1 , Andrew Bayley 1 , Charles Catton 1 , Padraig Warde 1 , Badr Id Said 1 , Alexandra Rink 1 , Robert Weersink 1 , Jeff Winter 1 , Bernadeth Lao 1 , Alejandro Berlin 1 , Peter Chung 1 1 Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada. 2 Department of Radiation Oncology, CancerCare Manitoba, Winnipeg, Canada. 3 Department of Biostatistics, University Health Network, Toronto, Canada. 4 Division of Radiation Oncology, BC Cancer - Vancouver, Vancouver, Canada. 5 Division of Radiation Oncology, London Regional Cancer Program, London, Canada Purpose/Objective: To report the outcomes, particularly late toxicity, of a prospective study of focal MR-guided HDR (MRgHDR) brachytherapy boost in combination with stereotactic body radiotherapy (SBRT) for localized prostate cancer. Material/Methods: Eligible patients included intermediate-risk (IR) and high-risk (HR) prostate cancer patients with MR-visible gross disease. Patients underwent a 15 Gy in 1 fraction MRgHDR focal brachytherapy boost to gross disease followed by SBRT either involving 30 Gy in 5 fractions to prostate-only in IR disease or 30 Gy in 5 fractions to prostate and pelvic nodes in HR disease. Outcomes included PSA, toxicity (CTCAE), and EPIC, which were conducted at baseline, and post-treatment follow-up visits at 1-, 3-, 6-months, and 1-, 2-, 3-, and 5-years. Androgen deprivation therapy (ADT) was administered at physicians’ discretion. Biochemical failure was defined according to Phoenix criteria (nadir + 2). Results: Between 2017-2023, 153 patients were enrolled of which 128 (84%) and 25 (16%) were IR and HR, respectively. Median age was 69 years old (range 49- 81), and median PSA was 8 ng/mL (range 2-53). ADT was administered in 46 (30%) patients, of which 22 (14%) received >6 months duration. Hydrogel spacer insertion was used in 72 (47%) patients. Median follow-up was 36 months (range 2-79). Median PSA nadir in patients without ADT was 0.35 (range 0.01- 4.75). Overall, 3-year biochemical control rate was 95.4%. No isolated local, regional or distant failures
Made with FlippingBook - Share PDF online