KLK3 and metastatic neoplasm: These findings, combined with data from GETUG-AFU 16 (which included patients up to PSA 2.0 ng/mL), suggest that SRT alone provides minimal benefit when PSA exceeds 4.0–5.0 ng/mL, at which point patients should be considered for systemic therapy or clinical trials due to the high likelihood of occult metastatic disease [50].