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.
Metastatic prostate cancer with clinical progression after the use of androgen-receptor pathway inhibitor, chemotherapy or any other life-prolonging therapy. Patient could have been treated previously by RadioLigand Therapy (RLT).
Performance Status < 3
Bone and/or lymph node metastases based on conventional (CT and bone scan) or metabolic imaging
Bone and/or lymph node metastases suitable for SRT, according to the investigator
Evidence of symptomatic metastases to the lungs, brain, peritoneum or liver
Evidence of diffuse metastatic spread to the bone marrow (e.g. positive super bone scan) or the cerebral spinal fluid as per bone scan (no lumbar puncture required).
Evidence of presence of symptomatic spinal cord compression with indication of neurosurgical decompression.
Patient with symptomatic and/or high-risk tumor volume-to-bone marrow reserve ratio > 50%