We analyzed the prognostic significance of clinical stage using extent of disease (EOD) grading system in 288 patients with prostate cancer between 1970 and 1994. The cause-specific survival rate for EOD4 was significantly lower (p < 0.01) than that for the other EOD categories. On the other hand, the cause-specific survival rate for EOD1 was significantly higher (p < 0.01) than that of the other EOD categories, and moreover, it was similar to the cause-specific survival rates for stage C and D1. The cause-specific survival rate of EOD1 and poorly differentiated cases was higher than that of EOD2 or 3 and well or moderately differentiated cases until 2 years after treatment, but after 3 years, the cause-specific survival rate for EOD1 and poorly differentiated cases was lower than that for EOD2 or 3 and well or moderately differentiated cases. These findings suggest that the volume of cancer is associated with the prognosis of prostate cancer that failed in radical treatment and that in stage D2, histological grade is more closely associated with the prognosis after treatment for 3 years.