Treatment outcome of radium-223 treatment for castration-resistant prostate cancer and bone metastases at a single university hospital

Background: We investigated therapeutic outcomes of Radium-223 (Ra-223) treatment in patients with metastatic castration-resistant prostate cancer (mCRPC) and bone metastases. Materials and Methods: Outcomes were retrospectively examined in 20 patients starting Ra-223 treatment at a single university hospital from January 2017 to January 2020. Results: Median patient age was 70 years. Median values included prostate specific antigen (PSA) 10.73 ng/ml, PSA doubling time (PSADT) 3.7 months, alkaline phosphatase (ALP) 315 IU/L, lactate dehydrogenase (LDH) 186 IU/L, neutrophil-to-lymphocyte ratio (NLR) 2.22, and Gleason score 9. Extent of disease (EOD) was 3 or more in 55%, and Eastern Cooperative Oncology Group performance status was 0 in 80%. 16 patients (80%) completed Ra-223 treatment. Ra- 223 was administered in 11 (55%) with ≤ 3 lines of treatment and 9 (45%) with ≥ 4. Concomitant drug was enzalutamide and abiraterone in 6 and 7 patients, respectively. Bone modifier agents (BMA) were used in 11 patients. Symptomatic skeletal events (SSE) occurred in 5 patients and were associated with abiraterone combination. BMA during Ra-223 treatment did not affect SSE. Median overall survival from initiation of Ra-223 treatment was 32.7 months. Prognosis was significantly better with PSADT ≤ 3 months, EOD ≤ 2, no SSE, no opioid use, and completion of Ra-223 treatment. PSA, LDH, NLR, PSADT, and Ra-223 treatment line after mCRPC were associated with Ra-223 completion. Anemia of Grade 3 occurred in 1 patient. Conclusion: Ra-223 treatment is safe, with good prognosis if completed. Combination treatment with abiraterone during Ra-223 treatment may cause SSE.