Abstract
BACKGROUND/AIM: Radium-223 treatment reduces the risk of death in patients with metastatic castration-resistant prostate cancer (CRPC). This study analyzed the prognostic factors in patients treated with radium-223 dichloride. PATIENTS AND METHODS: Patients who received radium-223 dichloride were retrospectively analyzed. Prostate-specific antigen (PSA) response and alkaline phosphatase (ALP) decline rates were analyzed. Overall survival (OS) was evaluated using Kaplan-Meier curves, and prognostic factors for OS were assessed using Cox proportional hazards analysis. RESULTS: Fifty-six patients were included in the study. The five-year OS rate in patients after diagnosis of CRPC was 62.2% [95% confidence interval (CI)=27.55-112.45], while the five-year OS rate in patients at the initiation of radium-223 treatment was 21.3% (95%CI=17.20-36.79). Six patients (11.1%) had a >50% PSA decline rate, and 10 (17.9%) had a >50% ALP decline rate. Cox proportional hazards analysis showed that PSA levels at the initiation of radium-223 treatment [hazard ratio (HR)=1.00; 95%CI=1.00-1.00; p=0.0054] and Gleason Pattern (GP) 5 (HR=5.42; 95%CI=1.08-27.27; p=0.0400) were associated with OS. Patients with GP 5 had a significantly poorer prognosis compared with patients with a GP ≤4. Early administration of radium-223 as a first- or second-line treatment was not associated with OS compared with late administration of radium-223 as a third-line or later treatment. CONCLUSION: GP 5 and high PSA levels at radium-223 initiation were associated with worse OS. Radium-223 as first- or second-line treatment was not associated with OS. Therefore, a treatment strategy for CRPC based on GP 5 is needed.