Focal therapy for primary tumor and metastases in de novo or recurrent oligometastatic prostate cancer: current standing and future perspectives

Abstract

Purpose: Focal therapy (FT) is gaining increasing acceptance in the management of localized prostate cancer particularly due to its favorable safety. Preliminary evidence suggests advantageous utilization of local treatment in the field of oligometastatic prostate cancer (OMPC). Since data on the utilization of FT in OMPC are scarce, we sought to summarize available evidence.

Methods: For this narrative comprehensive review, we employed PubMed^®, Web of Science™, Embase^®, Scopus^®, and clinicaltrial.gov databases and Google web search engine to seek peer-reviewed articles, published abstracts from international congresses, and ongoing trials in the English language using the terms "prostate cancer", "oligometastatic", "hormone-sensitive", "focal therapy", "focal treatment", "cryotherapy", "ablation", "cancer" as well as "metastasis-directed therapy. We focused on relevant publications on FT utilized in OMPC targeting the primary or metastatic sites as well as completed and ongoing clinical trials.

Results: Growing evidence points to distinct differences in the biologic behavior and molecular signaling processes of OMPC as compared to polymetastatic disease (PMPC). No established biomarkers are available to accurately identify OMPC yet, while several candidates are currently under investigation. The evolution of molecular imaging is set to aid in selecting patients benefitting most from local management. Differences between OMPC and PMPC should be considered when designing the optimal therapeutic strategy. While efficacy data for FT in comparison to standard care in OMPC are scarce, longer progression-free survival and time to castration resistance have been demonstrated for bone metastatic prostate cancer with the primary tumor treated by cryosurgery followed by androgen deprivation therapy (ADT) compared to ADT alone.

Conclusion: Ongoing research efforts are eagerly awaited to better characterize OMPC and establish customized strategies for patients with this condition.

Keywords: Ablation; Focal therapy; Hormone-sensitive; Oligometastatic; Prostate cancer.