High dose rate brachytherapy as monotherapy for localised prostate cancer

Background and purpose: To evaluate the oncological outcome of a three-implant high dose rate (HDR) brachytherapy (BRT) protocol as monotherapy for clinically localised prostate cancer. Material and methods: Between February 2008 and December 2012, 450 consecutive patients with clinically localised prostate cancer were treated with HDR monotherapy. The cohort comprised of 198 low-, 135 intermediate- and 117 high risk patients being treated with three single-fraction implants of 11.5 Gy delivered to an intraoperative real-time, transrectal ultrasound defined planning treatment volume up to a total physical dose of 34.5 Gy with an interfractional interval of 21 days. Fifty-eight patients (12.8%) received ADT, 32 of whom were high- and 26 intermediate-risk. Biochemical failure was defined according to the Phoenix Consensus Criteria and genitourinary/gastrointestinal toxicity evaluated using the Common Toxicity Criteria for Adverse Events version 3.0. Results: The median follow-up time was 56.3 months. The 60-month overall survival, biochemical control and metastasis-free-survival rates were 96.2%, 95.0% and 99.0%, respectively. Toxicity was scored per event with late Grade 2 and 3 genitourinary adverse events of 14.2% and 0.8%, respectively. Late Grade 2 gastrointestinal toxicity amounted 0.4% with no instances of Grade 3 or greater late adverse events to be reported. Conclusions: Our results confirm HDR BRT to be a safe and effective monotherapeutic treatment modality for clinically localised prostate cancer. (C) 2017 Elsevier B.V. All rights reserved. Radiotherapy and Oncology 126 (2018) 270-277