Conventional dose versus dose escalated radiotherapy including high-dose-rate brachytherapy boost for patients with Gleason score 9–10 clinical localized prostate cancer

Abstract

As several recent researches focus on the importance of Gleason 9–10, we examine the role of radiotherapy dose escalation in those patients. We analyzed 476 patients with Gleason score 9–10 prostate cancer treated with radiotherapy. Of them, 127 patients were treated with conventional-dose external beam radiotherapy (Conv RT) and 349 patients were treated with high-dose radiotherapy (HDRT; 249 patients received high-dose-rate brachytherapy boost + external beam radiotherapy [HDR boost] and 100 patients received intensity-modulated radiotherapy [IMRT]). We compared these treatment groups using multi-institutional retrospective data. The patients had a median follow-up period of 66.3 months. HDRT showed superior biochemical disease-free survival (bDFS) rate (85.2%; HDR boost 84.7% and IMRT 86.6%) to Conv RT (71.1%, p < 0.0001) at 5 years, with a hazard ratio of 0.448. There were borderline difference in prostate cancer-specific mortality (PCSM; 4.3% and 2.75%, p = 0.0581), and distant metastasis-free survival (DMFS; 94.4% and 89.6%, p = 0.0916) rates at 5-years between Conv RT and HDRT group. Dose escalated radiotherapy showed better bDFS, borderline improvement in PCSM, and equivocal outcome in DMFS in with clinically localized Gleason 9–10 prostate cancer.

Does brachytherapy boost improve survival outcomes in Gleason Grade Group 5 patients treated with external beam radiotherapy and androgen deprivation therapy? A systematic review and meta-analysis

“…Two studies directly compared OS after EBRT and EBRT + BT. There was a trend toward improved OS with BT boost (HR = 0.86; p = 0.08), but this was heavily weighted towards Kishan et al with only a minor contribution from Yamazaki et al (not shown) [14] , [22] .…”

“…A total of eight studies were selected for inclusion in the meta-analysis, all of which were retrospective series classified as Level 4 evidence [14] , [20] , [21] , [22] , [23] , [24] , [25] , [26] . Four reported data from a single institution, while the remaining four were multi-institutional.…”

“…If HRs were not directly reported in text, they were calculated using the extracted survival estimates and the corresponding numbers at risk. As Yamazaki et al reported survival data for two separate EBRT groups (i.e., conventional radiotherapy and intensity-modulated radiotherapy), this data was first combined before a HR was calculated with reference to the EBRT + BT group [14] .…”