PSA outcomes and late toxicity of single-fraction HDR brachytherapy and LDR brachytherapy as monotherapy in localized prostate cancer: A phase 2 randomized pilot study

PURPOSE: To evaluate the PSA outcomes and the late patient's reported health related quality of life (HRQOL) and toxicity after single-fraction High-Dose-Rate brachytherapy (HDRB) and Low-Dose-Rate brachytherapy (LDRB) for prostate cancer. METHODS: Men with low and favorable intermediate-risk prostate cancer across 3 centres were randomized between monotherapy brachytherapy with either Iodine-125 LDRB or 19 Gy single-fraction HDRB. Biochemical outcomes were evaluated using the Phoenix definition, PSA nadir and absolute PSA value < 0.4 ng/mL. Toxicities and HRQOL were recorded at 24 and 36 months. RESULTS: A total of 31 patients were randomized, 15 in the LDRB arm and 16 patients in the HDRB arm. After a median follow-up of 45(36-53) months, 3 patients in the HDRB arm experienced biochemical failure (p = 0.092). Nineteen Gy single-fraction HDRB was associated with significantly higher PSA nadir compared to LDRB (1.02 +/- 0.66 vs 0.25 +/- 0.39, p < 0.0001). Moreover, a significantly larger proportion of patients in the LDRB group had a PSA < 0.4 ng/mL (13/15 vs 2/16, p < 0.0001). For late Genito-Urinary, Gastro-Intestinal, and sexual toxicities at 24 and 36 months, no significant differences were found between the 2 arms. As for HRQOL, the IPSS and EPIC-26 urinary irritative score were significantly better for patients treated with HDRB over the first 36 months post-treatment (p=0.001 and p = 0.01, respectively), reflecting superior HRQOL. CONCLUSION: HDRB resulted in superior HRQOL in the irritative urinary domain compared to LDRB. PSA nadir was significantly lower in the LDRB group and a higher proportion of patients in the LDRB group reached PSA < 0.4 ng/mL. (C) 2021 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Automated summary

This study evaluated the PSA outcomes, HRQOL, and toxicity of single-fraction High-Dose-Rate brachytherapy (HDRB) and Low-Dose-Rate brachytherapy (LDRB) for prostate cancer patients. The results showed that HDRB resulted in superior HRQOL in the irritative urinary domain compared to LDRB, while the LDRB group had significantly lower PSA nadir and a higher proportion of patients reaching PSA < 0.4 ng/mL.