The 'oligometastatic' state, first proposed by Hellman and Weichselbaum in 1995, represents a distinct biological subset between localized and widely metastatic disease.1 In the context of modern systemic therapies and improved cancer detection, the oligometastatic phenotype is framed as a dynamic state within which local ablative therapies improve clinical outcome, including prolonging survival and achieving cure.2 The major subgroups within oligometastatic prostate cancer (OMPC) are de novo (synchronous) oligometastatic hormone sensitive prostate cancer (om-HSPC), oligorecurrent (metachronous) HSPC (or-HSPC) and oligoprogressive castrate resistant prostate cancer (op-CRPC). De novo om-HSPC patients present with an untreated primary tumor and metastases at diagnosis, or-HSPC patients experience a recurrence after definitive local therapy, and op-CRPC patients are characterized by limited new or progressing lesions and castrate levels of testosterone. The defining classifier for OMPC, so far, has been the lesion count on imaging, with a threshold of up to 5 metastases,3, 4, 5 but the definition will probably need to expand beyond simply counting.2 Identifying OMPC presents a unique therapeutic opportunity with metastasis-directed therapy (MDT), eradicating metastases with local therapy.

In OMPC, the local ablative treatment of choice is SBRT, given the low α/β ratio of prostate cancer, offering precise ablation, akin to a “noninvasive metastasectomy.” While level I evidence is lacking, emerging data from well-designed trials suggest that MDT improves local control, progression-free survival and has a favorable toxicity profile.2,6,7 This review aims to examine the current evidence on MDT across OMPC subtypes.