Analysis of survival of prostate cancer patients in Japan and the U.S.A.

The prognosis of U.S.A. patients with prostate cancer based on reports from the American College of Surgeons and Roswell Park Cancer Institute was compared with that of Japanese in Nagasaki and Gunma. There was more than a 10% difference in survival rate between the two countries. Several clinical parameters were analyzed to determine the basis for this difference. In general, stage distribution, metastatic sites, bone pain and alkaline phosphatase in the USA patients with Stage D disease were more severe than in the Japanese patients. Moreover the prostate cancer death rate in the USA was higher than that in Japan. However, only the distribution of pathological grade in the USA was better than that in Japan. From these results, it is difficult to conclude that prostate cancer in the USA is more aggressive than in Japan. The possibility of selection bias in these studies is discussed.