Randomised trial of external-beam radiotherapy alone or with high-dose-rate brachytherapy for prostate cancer: Mature 12-year results

Background and purpose: A randomised phase-III trial compared external beam radiotherapy (EBRT) alone with EBRT combined with high-dose-rate brachytherapy boost (HDR-BTb) in localised prostate adenocarcinoma. Previous analysis, at median follow up of 85 months, demonstrated improved relapse free survival (RFS) with EBRT + HDR-BTb. This data has now been updated with a median follow up of 131 months. Materials and methods: From December 1997 to August 2005, patients were assigned either to EBRT alone delivering 55 Gy in 20 fractions over 4 weeks or EBRT followed by a temporary high-dose-rate implant delivering 2 x 8.5 Gy over 24 h. The primary endpoint was RFS defined by a PSA rise >= 2.0 mu g/l above nadir, clinical progression or death. Actuarial survival rates and Hazard Ratios (HRs) were calculated using the Kaplan-Meier method and Cox's Proportional Hazard Model, respectively. Secondary endpoints were overall survival (OS), urinary and bowel toxicity. Results: One hundred and six patients received EBRT alone and 110 EBRT + HDR-BTb. Median time to relapse was 137 months in the HDR-BTb arm compared to 82 months for EBRT alone (p = 0.01). A 27% risk of recurrence with EBRT alone was observed (p = 0.001), resulting in a 21% improvement in RFS at 12 years with EBRT + HDR-BTb. In multivariate analysis treatment arm, risk category and no androgen deprivation therapy were significant covariates for risk of relapse. Differences in overall survival were not significant. Conclusion: At 12 years there remains a significant improvement in RFS after EBRT + HDR-BTb; both treatments were equitoxic for severe late urinary and bowel events and urethral strictures. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study compared the efficacy of EBRT + HDR-BTb with EBRT alone in localized prostate adenocarcinoma, showing a significant improvement in RFS with EBRT + HDR-BTb. At 12 years, there was a 21% improvement in RFS with EBRT + HDR-BTb, while both treatments were found to be equally toxic with severe late urinary and bowel events.