Protocol summary of a randomized controlled phase III trial for confirming the superiority of local radiotherapy for prostate cancer patients with high-volume metastasis sensitive to hormonal therapy: the JCOG2011 (HimeRT study).

Local therapy is not considered a standard treatment option for patients with high-volume metastatic prostate cancer. Our research group's previous retrospective study indicated potential benefits of local radiotherapy (LRT) for some high-volume metastatic prostate cancer patients, but prospective studies have yet to confirm these findings. We have thus planned a multicenter, open-label, randomized controlled phase III trial to confirm the efficacy of adding LRT to systemic hormonal therapy with androgen deprivation therapy plus an androgen receptor pathway inhibitor in a population of high-volume metastatic prostate cancer patients for whom the hormonal therapy is effective for 6 months. The primary endpoint is failure-free survival, defined as the time from randomization to prostate-specific antigen progression, radiological progression, clinical progression, or death from any cause. We aim to enroll 360 patients from 56 institutions over a 4-year period. This trial is registered at the Japan Registry of Clinical Trials (study no. jRCT1031220676).