A comparison of prostate cancer patients in Japan and the USA.

Clinical characteristics of prostate cancer patients were analyzed to compare the rates of progression of prostate cancer between patients in Japan (Gunma Urological Oncology Study Group: GUOSG) and the USA (Roswell Park Cancer Institute: RPCI), between 1980 and 1989. The stage of disease was more advanced and the age was greater in GUOSG patients compared with RPCI patients. However, the prostate cancer death rate of stage D patients at RPCI was significantly higher than that of the GUOSG. Moreover, the survival rate of stage A patients in the GUOSG was better than that of RPCI patients. The possibility of biases which may affect both the clinical characteristics and survival rates in the 2 populations studied is discussed. To determine whether there is a real difference in the rate of prostate cancer growth between the 2 countries will require a prospective study, ideally conducted in large population groups.