Usefulness of J-CAPRA score for high-risk prostate cancer patients treated with carbon ion radiotherapy plus androgen deprivation therapy.

Background: A novel risk assessment method, Japan Cancer of the Prostate Risk Assessment, has been developed based on database of patients receiving primary androgen deprivation therapy. To investigate the usefulness of Japan Cancer of the Prostate Risk Assessment for non-metastatic, high-risk prostate cancer patients treated with carbon ion radiotherapy plus androgen deprivation therapy.

Methods: Patients with non-metastatic, high-risk prostate cancer (T3, initial prostate specific antigen level ≥20 ng/ml, and/or Gleason score ≥8) were included. The patients were treated with carbon ion radiotherapy (the total dose from 57.6 Gy (relative biological effectiveness)/16 fractions to 66.0 Gy(relative biological effectiveness)/20 fractions), and neoadjuvant as well as adjuvant androgen deprivation therapy for at least 24 months.

Results: Four hundred and twenty-six patients were included with the median follow-up of 68.1 months. Of 426, 210 (49.3%), 270 (63.4%) and 251 (58.9%) had Gleason 8-10, prostate specific antigen ≥20 ng/ml and T3, respectively. The 10-year progression-free and cause-specific survival rates in Japan Cancer of the Prostate Risk Assessment 1-2 group (76.5 and 98.9%) were significantly better than those in Japan Cancer of the Prostate Risk Assessment 3-6 group (52.6 and 93.1%), (P < 0.001 and P = 0.044, respectively). The median progression-free survivals in the Japan Cancer of the Prostate Risk Assessment 1-2 and 3-6 groups were 158.9 months and 125.9 months (95% confidence interval: 108.6-143.2 months), respectively.

Conclusions: For non-metastatic, high-risk prostate cancer patients treated with carbon ion radiotherapy plus androgen deprivation therapy, Japan Cancer of the Prostate Risk Assessment score was useful for predicting the progression-free and cause-specific survivals.