[Biliary tract cancer]

The proportion of mortalities from biliary tract cancer, which includes gallbladder and extrahepatic bile duct cancers, is only 5% of all deaths from malignant neoplasms in Japan. Epidemiologists, however, are concerned about the cancer due to its peculiar geographic distribution. In addition, they have also noted the recent decreasing trends in mortality rates, especially among females. The most probable explanation is either a change in the effects of risk factors or the development of abdominal ultrasound sonography and laparoscopic cholecystectomy, or both. Further research should be directed towards an analysis of the causes of this decreasing trend.