Stereotactic radiotherapy in oligometastatic prostate cancer: a single-center experience

INTRODUCTION: Oligometastatic prostate cancer represents an intermediate disease state potentially amenable to metastasis-directed therapies such as stereotactic body radiotherapy (SBRT), aiming to delay disease progression and postpone systemic treatment. AIM: The aim of this study was to evaluate the real-world outcomes of SBRT in patients with hormone-sensitive oligometastatic prostate cancer. METHODS: This single-center retrospective study included patients with hormone-sensitive oligometastatic prostate cancer staged with PSMA PET and treated with SBRT at a tertiary center between January 2022 and March 2024. The primary endpoint was hormone therapy-free survival (HTFS). Secondary endpoints included event-free survival (EFS), local control, overall survival (OS), and toxicity. RESULTS: A total of 34 patients were included, predominantly with low-volume disease (79.4% with a single metastasis). SBRT achieved significant biochemical responses (PSA50 in 69.7%; median PSA nadir 0.19 ng/mL). HTFS rates were 85.2% and 74.6% at 12 and 24 months, respectively, with the median not reached. Median EFS was 16.2 months. Local control was 84.2%, and 24-month OS was 87.8%. Toxicity was minimal, with no grade ≥ 3 adverse events. A PSA nadir ≤ 0.20 ng/mL and ISUP ≤ 2 were associated with improved outcomes. CONCLUSIONS: SBRT may delay systemic therapy without compromising disease control in oligometastatic prostate cancer. Its integration into personalized treatment strategies, guided by biological and biochemical factors, represents a promising therapeutic approach.