Proffered Presentations Archive

UK & Ireland Prostate Brachytherapy Conference 2024

Abstract number 17 

Analysis of Survival Following Low-Dose Rate Brachytherapy Boost for Prostate Cancer at the Royal Surrey Hospital: A Comparison with the Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy (ASCENDE-RT) Trial

Mohamed Metawe, Santiago Uribe-Lewis, Christos Mikropoulos, Philip Turner, Sophie Otter, Stephen Langley
Royal Surrey Hospital NHS Foundation Trust 

Purpose: Comparing dose-escalated external beam boost (DE-EBRT) with low-dose-rate brachytherapy boost (LDR-BB), and at a median follow-up of 10 years, ASCENDE-RT published its updated results on time to progression (TTP) and survival endpoints in 2022, showing a clear TTP benefit of LDR-BB over DE-EBRT (10-year Kaplan-Meier TTP estimates of 85% and 67%, respectively). Our study aimed to evaluate LDR-BB outcomes in a high-volume prostate brachytherapy centre in comparison to ASCENDE-RT LDR-BB arm, and additionally compare our outcomes between the eras of two-stage (2S) and one-stage real-time intra-operative planning (4D) brachytherapy techniques. 

Methods: Using our prospectively collected patient database, a detailed analysis of patients treated at the Royal Surrey Hospital with LDR-BB was conducted. Patients selected for analysis must have received androgen deprivation therapy (ADT) and external beam radiotherapy with a brachytherapy boost and had an implant date recorded. Relapse was defined as having annotation on the database, with dates, for clinical progression, withdrawal due to receiving treatment other than brachytherapy, salvage therapy, or evidence of biochemical failure, using the Phoenix definition (nadir PSA + 2 ng/mL), when a patient has a baseline and at least 3 PSA follow-up values. 

Results: In our hospital, 734 patients received LDR-BB (40% with intermediate-risk and 60% with high-risk disease) 126 from 1999 to 2008 with 2S and 608 from 2009 to 2023 with 4D techniques. The 10-year relapse-free survival (RFS) rates were 94% for 4D and 81% for 2S (p<0.0001), compared to ASCENDE-RT’s 85%. Ten-year OS was 93% for 4D and 87% for 2S (p=0.00088), versus ASCENDE-RT’s 80%. Ten-year prostate cancer-specific survival (PCSS) rates were 97% and 93%, for 4D and 2S, respectively (p=0.0027), compared to 95% in ASCENDE-RT. 

Conclusion: Our study showcases favourable 10-year survival outcomes compared to ASCENDE-RT, with superior RFS, OS and PCSS observed in the 4D era compared to 2S. 

References: 1. Oh J, Tyldesley S, Pai H, McKenzie M, Halperin R, Duncan G, et al. An Updated Analysis of the Survival Endpoints of ASCENDE-RT. Int J Radiat Oncol Biol Phys. 2023 Apr 1;115(5):1061-1070.