Proffered Presentations Archive

UK & Ireland Prostate Brachytherapy Conference 2024

Abstract number 19 

High dose-rate salvage brachytherapy in prostate cancer with isolated seminal vesicle relapse

Milan Anjanappa, Amani Chowdhury, Roberto Alonzi, Peter Ostler, Robert Hughes, Peter Hoskin
Mount Vernon Cancer Centre 

Purpose: To evaluate biochemical control rates after high dose-rate (HDR) salvage brachytherapy in patients with isolated seminal vesicle (SV) recurrence. 

Methods: A single-institution retrospective analysis (2013-2023) of patients undergoing salvage HDR brachytherapy for prostate cancer with isolated seminal vesicle relapse was conducted. Toxicity was graded using the Radiation Therapy Oncology Group (RTOG) criteria. Recurrence after salvage was defined as PSA 2.0ug/L above nadir or radiological evidence of disease. 

Results: Between 2013-2023, 134 patients underwent salvage brachytherapy for locally recurrent prostate cancer. Of these, 16 cases had an isolated SV relapse. Prior primary treatment included: external beam radiotherapy (4), low-dose-rate seed brachytherapy (8), high intensity focused ultrasound (1), prostatectomy and prostate bed radiotherapy (1) and HDR brachytherapy (1). The median time to biochemical failure from initial treatment was 72 months. Median PSA at time of salvage brachytherapy was 4.34ug/L. In 15 cases a single 19Gy dose was delivered; the remaining patient received 26Gy in 2 fractions using a single implant procedure. The clinical target volume (CTV) ranged from 3.4-20.12cc and planning target volume (PTV) 9.8 – 37.3cc. The median follow-up was 29 months (range 1-88 months) and the median relapse-free interval was 38.5 months (range 6 months – not reached). The median time to PSA nadir after salvage brachytherapy was 10.5 months (range 3-16 months). 9 cases were found to have subsequent disease relapse: local (5 cases), regional (3 cases) and distant (1 case). Among the 5 cases with local relapse, 2 recurred within the prostate, 2 within the re-treatment volume and 1 relapsed within the seminal vesicle outside of the re-treatment volume. Late grade 3 side effects were experienced in 4 patients (3 patients developed a urethral stricture; 1 patient required a trans-urethral resection of the prostate). 

Conclusion: Isolated SV recurrence is uncommon and can be salvaged successfully with HDR brachytherapy with minimal toxicity.