Darolutamide + Consolidation Radiotherapy in Advanced Prostate Cancer Detected by PSMA

This study explores the use of local consolidation therapy in the setting of Darolutamide in the initial diagnosis of metastatic castrate resistant prostate cancer (mCRPC). In the chemotherapy naïve mCRPC setting, the pattern of disease is of limited volume metastases (1-5) in 34%-40% of cases. As progression at known sites of macroscopic disease is the predominant cause of failure on systemic therapies, local consolidation therapy with stereotactic ablative body radiotherapy (SABR) may improve progression free survival (PFS) and overall survival (OS). This approach has been tested in the setting of lung cancer, in which consolidation SABR has resulted in OS benefit (HR of 0.40) in phase II studies. The novel approach of local consolidation therapy has not been tested as yet in mCRPC. The secondary objective of this study proposal is to better understand the pattern of disease distribution at first diagnosis of CRPC. Previous studies have used conventional bone scan and CT imaging, and with these investigations the proportion of patients that are 'M0' is \~35%1. However, in the new era of PSMA PET, which is far more sensitive than conventional imaging, there exists a new group of men who are M0 on conventional imaging but are M1 on PSMA PET staging. Thus, in the DECREASE study population, we expect the vast majority of patients with conventionally imaged 'M0 CRPC' will have disease detectable on PSMA PET scanning. In this context, the central hypothesis of this trial is that the addition of consolidation radiotherapy to darolutamide to PSMA detected sites of disease will improve the clinical outcome of patients compared to those patients receiving darolutamide alone.