Japan Cancer of the Prostate Risk Assessment for combined androgen blockade including bicalutamide: Clinical application and validation

Abstract

The Japan Cancer of the Prostate Risk Assessment was developed as a risk stratification instrument for patients undergoing primary androgen deprivation therapy. However, there have been no studies to validate the accuracy of the Japan Cancer of the Prostate Risk Assessment in predicting clinical outcomes. We examined whether the clinical outcomes of patients treated with combined androgen blockade could be stratified using the Japan Cancer of the Prostate Risk Assessment. A total of 319 patients with prostate cancer treated with luteinizing hormone-releasing hormone agonist plus bicalutamide were included in this analysis. Progression-free survival, cause-specific survival and overall survival were compared among patients divided according to the prostate-specific antigen level at diagnosis, Gleason score on biopsy specimens, tumor-nodes-metastasis classification and Japan Cancer of the Prostate Risk Assessment score. The median age of the patients was 75 years, and the median prostate-specific antigen at diagnosis was 25.4 ng/mL. A total of 102 patients (32.0%) had lymph node and/or distant metastases. On univariate analysis, the factors adopted in the Japan Cancer of the Prostate Risk Assessment points were significant predictors of progression-free survival. On multivariate analysis, clinical T stage and M stage were significant predictors of progression-free survival. The probabilities of progression-free survival and cause-specific survival were significantly different among the groups categorized according to the Japan Cancer of the Prostate Risk Assessment risk strata. The probability of overall survival in the low-risk group was higher than in the other groups. The progression-free survival, cause-specific survival and overall survival of prostate cancer patients treated by combined androgen blockade with bicalutamide were stratified by the Japan Cancer of the Prostate Risk Assessment. The Japan Cancer of the Prostate Risk Assessment score is clinically useful as a predictor of the prognosis of prostate cancer treated with combined androgen blockade.