A single-center study on predicting outcomes of primary androgen deprivation therapy for prostate cancer using the Japan Cancer of the Prostate Risk Assessment (J-CAPRA) score

Objective: Japan Cancer of the Prostate Risk Assessment scores are reportedly useful for predicting progression-free survival after primary androgen deprivation therapy of prostate cancer patients. This study validated the risk assessment at a single institution.

Methods: We studied 255 prostate cancer patients given primary androgen deprivation therapy. Progression-free survival, cause-specific survival and overall survival were analyzed according to Japan Cancer of the Prostate Risk Assessment score-based risk classification. Cases with lymph node or distant metastases were subdivided by the risk classification.

Results: Ages ranged from 50 to 90 years (median: 76.5). Observation periods were 2-199 (median: 46.5) months. Primary androgen deprivation therapy includes combined androgen blockade in 150 cases (58.8%), uncombined luteinizing hormone-releasing hormone agonist in 97 (38.0%) and uncombined anti-androgenic agent in 8 (3.2%). Risk classified by Japan Cancer of the Prostate Risk Assessment scores was low in 104 cases (40.8%), intermediate in 86 (33.7%) and high in 65 (25.5%). The 5-year/10-year progression-free survival rates were 100%/80.8% in the low-risk, 82.3%/69.5% in the intermediate-risk and 34.7%/16.5% in the high-risk group. The 5-year/10-year cause-specific survival rates were 100%/100% in the low-risk, 90.7%/58.2% in the intermediate-risk and 63%/30.8% in the high-risk group. The 5-year/10-year overall survival rates were 87.5%/78.5% in the low-risk, 76.2%/43.1% in the intermediate-risk and 54.9%/25.4% in the high-risk group. For lymph node metastasis, cause-specific survival differed minimally between the intermediate- and high-risk groups (P = 0.1118). For distant metastasis, cause-specific survival differed significantly between the intermediate- and high-risk groups (P = 0.0264).

Conclusions: Japan Cancer of the Prostate Risk Assessment score-based risk classification is useful for predicting post-primary androgen deprivation therapy progression-free survival, cause-specific survival and overall survival. Subtyping patients based on Japan Cancer of the Prostate Risk Assessment scores is particularly useful for predicting cause-specific survival with distant metastasis from prostate cancer.