A Phase 2 Randomized Pilot Study Comparing High-Dose-Rate Brachytherapy and Low-Dose-Rate Brachytherapy as Monotherapy in Localized Prostate Cancer

Purpose To compare health-related quality of life (HRQOL) of high-dose-rate brachytherapy (HDRB) versus low dose-rate brachytherapy (LDRB) for localized prostate cancer in a multi-institutional phase 2 randomized trial. Methods and Materials Men with favorable-risk prostate cancer were randomized between monotherapy brachytherapy with either Iodine-125 LDRB to 144 Gy or single-fraction Iridium-192 HDRB to 19 Gy. HRQOL and urinary toxicity were recorded at baseline and at 1, 3, 6, and 12 months using the Expanded Prostate Cancer Index Composite (EPIC)-26 scoring and the International Prostate Symptom Score (IPSS). Independent samples t test and mixed effects modeling were performed for continuous variables. Time to IPSS resolution, defined as return to its baseline score ±5 points, was calculated using Kaplan-Meier estimator curves with the log-rank test. A multiple-comparison adjusted P value of ≤.05 was considered significant. Results LDRB and HDRB were performed in 15 and 16 patients, respectively, for a total of 31 patients. At 3 months, patients treated with LDRB had a higher IPSS score (mean, 15.5 vs 6.0, respectively; P = .003) and lower EPIC urinary irritative score (mean, 69.2 vs 85.3, respectively; P = .037) compared with those who received HDRB. On repeated measures at 1, 3, 6, and 12 months, the IPSS (P = .003) and EPIC urinary irritative scores (P = .019) were significantly better in the HDR arm, translating into a lower urinary toxicity profile. There were no significant differences in the EPIC urinary incontinence, sexual, or bowel habit scores between the 2 groups at any measured time point. Time to IPSS resolution was significantly shorter in the HDRB group (mean, 2.0 months) compared with the LDRB group (mean, 6.0 months; P = .028). Conclusions HDRB monotherapy is a promising modality associated with a lower urinary toxicity profile and higher HRQOL in the first 12 months compared with LDRB.