A randomized phase II clinical trial (RADIOSA trial: Radioablation with or without Androgen DeprIvation therapy in metachronous prostate cancer OligometaStAsis). The aim is to compare time to progression between the two study arms: SBRT only or SBRT and hormonotherapy (ADT). The primary objective is to compare the progression-free survival (PFS) defined as the absence of new metastatic lesions (local, regional or distant) between the two arms. The secondary endpoints include the comparison of overall survival (OS), biochemical progression-free survival (BPFS), ADT-free survival, local control, treatment-induced acute and late toxicity, time to castration-resistant disease and QoL between the two arms; the development of a dedicated biobanking (collection of plasma and serum) for further biological investigation of predictive/diagnostic factors for personalized treatment; the preliminary evaluation of prognostic biomarkers; the correlation between imaging-derived parameters and treatment outcome.