High-dose-rate brachytherapy as a monotherapy for prostate cancer—Single-institution results of the extreme fractionation regimen

Abstract Purpose We report a single-institution retrospective analysis of the outcomes, disease control, and toxicity of high-dose-rate (HDR) brachytherapy used as the only treatment modality (monotherapy) for localized prostate cancer. Methods Between 2006 and 2012, 77 patients with diagnosed prostate cancer were treated with HDR brachytherapy as a monotherapy. The prescribed dose was 45 Gy in three separate implants 21 days apart, with single fraction per implant. Of the 77 patients, 67 (87%) received hormonal therapy. Prostate-specific antigen failure was defined according to Phoenix consensus, as nadir + 2 ng/mL. Toxicity was scored according to Common Terminology Criteria for Adverse Events, version 4.03. Results The median followup time was 57 months (4.75 years). The 5-year actuarial overall survival was 98.7%, biochemical control 96.7%, local control 96.9%, and metastasis-free survival 98.4%. Younger age at the beginning of brachytherapy predicted the onset of bounce phenomenon. There were no Grade 3 or higher acute toxicities detected, and Grade 2 genitourinary acute toxicity developed in 19 patients (24.6%). There were no Grade 2 gastrointestinal complications. No Grade 4 or 5 late toxicity was detected. There were also no Grade 3 gastrointestinal toxicities detected. One patient (1.3%) underwent transurethral resection of the prostate because of Grade 3 urethral stenosis and urinary retention. A total of 26 patients (33.8%) developed Grade 2 late toxicity. Conclusions HDR brachytherapy as monotherapy for localized prostate cancer was feasible, effective, and had acceptable toxicity profile.