Local therapy for oligometastatic prostate cancer

Traditionally, systemic therapy based on androgen deprivation therapy (ADT) has been the primary approach for treating metastatic prostate cancer. Local therapies targeting metastatic lesions have rarely been employed for cancer control. However, the advent of next-generation imaging modalities, such as choline positron emission tomography (PET), whole-body magnetic resonance imaging, and prostate-specific membrane antigen (PSMA)-PET, has enabled the detection of oligometastases that were previously undetectable using conventional imaging techniques, such as computed tomography and bone scintigraphy. This has led to increased attention to local therapy for oligometastatic prostate cancer with cancer control. Oligometastatic prostate cancer can be classified into three categories: de novo oligometastases (oligometastases identified at initial diagnosis), oligorecurrence (oligometastases arising after radical treatment of primary tumor), and oligoprogression (activation of oligometastases following ADT failure). Evidence from randomized controlled trials (RCTs) supports the efficacy of local therapy in these contexts. The phase III STAMPEDE trial demonstrated that the addition of prostate radiotherapy to ADT improved the overall survival in patients with de novo low-volume metastatic prostate cancer. Furthermore, in the STOMP and ORIOLE trials, phase II RCTs have shown that metastasis-directed therapy significantly prolongs progression-free survival (PFS) in patients with oligorecurrent prostate cancer after radical treatment. For oligoprogressive castration-resistant prostate cancer, the phase II ARTO trial demonstrated that the addition of radiotherapy targeting oligometastases to first-line abiraterone acetate and prednisone treatments improved PFS. With the global adoption of PSMA-PET, local therapy for primary tumor and metastases in oligometastatic prostate cancer is expected to play an increasingly prominent role in the future.