Efficiency of pretreatment risk stratification systems for prostate cancer in a japanese population treated with radical prostatectomy

Objective: To determine whether the currently available pretreatment risk classification systems are applicable in Japanese prostate cancer patients. Methods: Using data obtained from 1264 consecutive patients with prostate cancer treated with radical prostatectomy at four hospitals in Japan, biochemical recurrence-free survival rates were estimated and compared between the D'Amico, the National Institute for Health and Clinical Excellence, the Cancer of the Prostate Strategic Urological Research Endeavor, the National Comprehensive Cancer Network, and the European Society of Medical Oncology risk groups by using the Kaplan-Meier method and log-rank test. Results: The 5-year biochemical recurrence-free survival rates in the D'Amico low-, intermediate-, and high-risk groups were 88.3%, 84.7% and 66.9%, respectively (low and intermediate risk vs high risk, P<0.001). The 5-year biochemical recurrence-free survival rates in the National Institute for Health and Clinical Excellence, National Comprehensive Cancer Network, and European Society of Medical Oncology low-, intermediate- and high-risk groups were 88.3%, 84.3%, and 60.3%, respectively (low and intermediate risk vs high risk, P<0.001). The 5-year biochemical recurrence-free survival rates in the Cancer of the Prostate Strategic Urological Research Endeavor low-, intermediate-, and high-risk groups were 90%, 83.5% and 60.3%, respectively (low and intermediate risk vs high risk, P<0.001). Low- and intermediate-risk groups according to any of the risk stratification systems did not show significant differences in biochemical recurrence-free survival. Conclusion: Current risk stratification systems do not discriminate between low- and intermediate-risk groups in the Japanese population. A novel, pretreatment risk stratification system including other prognostic factors is necessary for an adequate prostate cancer risk assessment in the Japanese population.