HIghly MetAstatic Life Prolonging Therapy-Resistant Prostate Cancer: Role of Stereotactic Radiotherapy for Bone and Lymph Node Metastases (HIMARS)

The investigators propose redefining this concept by focusing on volume rather than the number of metastases. To achieve this, the investigators aim to determine the Maximum Tolerated Volume (MTV) of metastatic lesions treatable with SRT (Stereotaxic radiotherapy) in a phase 1 study. In this study, the investigators will recruit patients with high-volume metastatic disease in bones or lymph nodes and progressively irradiate a volume-escalated subset of the total lesions. The selection will prioritize lesions at higher risk of causing pain or complications, such as fractures, spinal compression, or vascular compression. The investigators hypothesis is that SRT targeting multiple metastases (with a total volume ≤ MTV) will extend the duration without refractory pain and/or tumor-related complications in patients with castration-resistant and chemo-refractory prostate cancer.

NCT Number	NCT06978296
Lead Sponsor	Institut Cancerologie de l'Ouest
Conditions	Prostate Cancer Metastatic Disease, Oligometastatic Prostate Cancer (OMPC)
Enrollment	18 participants
Start Date	2026-06-01
Primary Completion	2028-05-01 (estimated)
Study Completion	2030-07-01 (estimated)
Updated on ClinicalTrials.gov	2026-06-04