Descriptive epidemiology of subsites of cancers of the liver, biliary tract and pancreas in Japan.

Recent time trends (1979-1987) and geographical distributions in mortalities from subsites of cancers of the hepato-biliary-pancreatic system have been investigated on the basis of the vital statistics of Japan. The corrected age-adjusted mortality rates (CAAMRs) were calculated to eliminate the influence of the proportion of subsite-unknown cancers. During the above period, the CAAMR for intrahepatic bile duct cancer increased by a relatively high extent (2.0-fold in males and 1.67-fold in females), and those for cancers of the gallbladder, extrahepatic bile duct and pancreas (head and other parts) increased to a moderate extent (1.2-1.4-fold). The CAAMR for primary liver cancer showed an increasing trend in males and a decreasing trend in females. The CAAMR for cancer of the ampulla Vater changed little during the period. A clear cluster of prefectures with high CAAMRs was observed in the northern part of Japan for cancers of the extrahepatic bile duct and pancreatic head. Clusters of prefectures with high CAAMRs for cancer of the gallbladder and ampulla Vater were observed in the mid-northern part of Japan, especially on the Japan Sea side. The CAAMR for primary liver cancer was high in the Island of Kyushu and some western parts of Japan, and low in the northern part of Honshu Island. No clear clusters of prefectures with high CAAMRs were observed for cancers of the intrahepatic bile duct and pancreas, other than for the pancreatic head.