Treatment of the Primary Tumor in Metastatic Prostate Cancer: Current Concepts and Future Perspectives.

CONTEXT Multimodal treatment for men with locally advanced prostate cancer (PCa) using neoadjuvant/adjuvant systemic therapy, surgery, and radiation therapy is being increasingly explored. There is also interest in the oncologic benefit of treating the primary tumor in the setting of metastatic PCa (mPCa). OBJECTIVE To perform a review of the literature regarding the treatment of the primary tumor in the setting of mPCa. EVIDENCE ACQUISITION Medline, PubMed, and Scopus electronic databases were queried for English language articles from January 1990 to September 2014. Prospective and retrospective studies were included. EVIDENCE SYNTHESIS There is no published randomized controlled trial (RCT) comparing local therapy and systemic therapy to systemic therapy alone in the treatment of mPCa. Prospective studies of men with locally advanced PCa and retrospective studies of occult node-positive PCa have consistently shown the addition of local therapy to a multimodal treatment regimen improves outcomes. Molecular and genomic evidence further suggests the primary tumor may have an active role in mPCa. CONCLUSIONS Treatment of the primary tumor in mPCa is being increasingly explored. While preclinical, translational, and retrospective evidence supports local therapy in advanced disease, further prospective studies are under way to evaluate this multimodal approach and identify the patients most likely to benefit from the inclusion of local therapy in the setting of metastatic disease. PATIENT SUMMARY In this review we explored preclinical and clinical evidence for treatment of the primary tumor in metastatic prostate cancer (mPCa). We found evidence to support clinical trials investigating mPCa therapy that includes local treatment of the primary tumor. Currently, treating the primary tumor in mPCa is controversial and lacks high-level evidence sufficient for routine recommendation.