1993 Volume 84 Issue 6 Pages 1110-1118
Histopathological comparison of clinical prostatic adenocarcinoma between Japan and the United States (US) has been made with retrospective analyses on 1, 037 and 987 cases, respectively. All cases were histologically evaluated by the same pathologist (M. H.) without previous knowledge of clinical information according to application of the Japanese General Rules for Prostatic Cancer (JGRPC) based on the predominant degree of histological differentiation, the nuclear grading by WHO classification and the Gleason grading systems. The age distribution of the patients was slightly different among both groups. However, this difference appeared not to be essential, because there existed difference of the date on diagnosis between two groups. Even though considering this time difference on registration, much more cases from Japan had stage D disease. The observed incidence of the histological differentiation classified by JGRPC among over-all cases did not show significant difference, however, the incidence among the cases with same stage between two groups differed with some statistical significance. Much more cases from the US fell in well differentiated adenocarcinoma and frequency of moderately differentiated adenocarcinoma was higher in the Japanese even in the cases diagnosed at advanced stages. The observed incidence of nuclear grade 3 was also higher in the Japanese. Gleason primary and secondary grade 5 and score 9-10 appeared more frequently in the cases from Japan. From the results of the patient survival analysed by life table form, the degree of histological differentiation based on JGRPC and WHO nuclear grading revealed significant correlation to the prognosis of the patient in either cases from Japan or the US. However, the Japanese cases with poorly differentiated and/or grade 3 of nuclear grade tended to have much more poor prognosis compared to the cases with the same histological group from the US. The mortality rates of the Japanese cases with 7-10 of Gleason grade-stage categories were much higher than the values of those from the US. However, the cancer mortality rates closely correlated with this grade-stage categories even in the cases from Japan and the curves plotted with mortality rate in each category on both groups revealed quite similarity. These results may suggest that much more clinical prostatic adenocarcinomas from Japan seem to have delay on detecting time and higher histological grade with poorer prognosis, in addition, are supposed to have different characteristics on clinical courses.
