Biliary tract cancer is a rare cancer in most parts of the world, but it is relatively common in some countries and ethnic groups, such as Japan, Central and South America, eastern Europe and in American Indians, and Hispanics. In some countries, such as Japan, Sweden, Finland and Italy, the age adjusted mortality of biliary tract cancer has been increasing, whereas in females in some other countries--Israel, The Netherlands, USA, Canada, Federal Republic of Germany, etc--mortality has been declining. The reasons for these geographical or ethnic variations and time trends for biliary tract cancer are not clear, but some unknown environmental risk factors or a genetic susceptibility are suspected. Not many analytical epidemiological studies on biliary tract cancer have been conducted yet and little is known about its aetiology apart from a close association with gall stones and a female preponderance of gall bladder cancer. Besides gall stones, some other factors such as obesity, pregnancy, female sex hormones, exposure in rubber and some other chemical industries and genetic factors have been suspected of being associated with gall bladder cancer directly or indirectly through cholelithiasis. As an artificial factor, the effect of the prevalence of cholecystectomy on biliary tract cancer must be considered. More studies are needed in the future to elucidate the aetiology of biliary tract cancer and to establish measures to prevent this cancer.
Histograms of all age-standardized death certification rates from 26 cancers or groups of cancers and total cancer mortality for the most recent calendar quinquennium (generally 1985-89) were produced for 55 countries: 26 in Europe, the former Soviet Union (USSR), three in North America, 13 in Latin America and the Caribbean, two in Africa, eight in Asia and two in Oceania, providing interpretable data to the World Health Organization database. Major differences were observed for all common cancer sites, including stomach (49/100,000 males in Costa Rica, 38 in the USSR and Japan vs 5/100,000 in the United States), intestines (over 25/100,000 males in Czechoslovakia, Hungary and New Zealand vs 10-15/100,000 in Japan and Southern Europe and less than 5/100,000 in most Latin American and Asian countries), lung (over 70/100,000 in Belgium, Scotland, The Netherlands, Czechoslovakia and Hungary, and less than 20/100,000 in most Latin American and Asian countries; over 20/100,000 females in Britain, Hong Kong, the United States and Denmark vs less than 5/100,000 in France, Spain and again most areas of Asia and Africa providing data; breast (over 25/100,000 females in Great Britain, New Zealand, Belgium, The Netherlands and Uruguay, vs less than 10/100,000 in Japan, Hong Kong and most Latin American countries). Thus, there was over a fivefold variation in total cancer mortality for both sexes, the highest rates being in Hungary (237/100,000) and Czechoslovakia (229/100,000) for males, and in Denmark (142/100,000) and Scotland (138/100,000) for females. Although problems of validity and reliability of cancer death certification, mostly in developing countries, may in part explain this variation, these substantial differences are at least in part real and essentially reflect, besides the impact of breast cancer in females and of stomach and colorectal cancer in both sexes, the different spectrum of the tobacco-related lung cancer epidemic in the two sexes and in various areas of the world.
Histograms of age-standardized (world standard) death certification rates from 24 cancers or groups of cancers and total cancer mortality for the 5-year calendar period 1990-94 were provided for 55 countries of the world: 35 countries in Europe, two in North America, nine in Latin America, two in Africa, five in Asia and two in Oceania. The highest male lung cancer mortality rates worldwide were registered in Hungary (82/100000), the Czech Republic and the Russian Federation, followed by other eastern European countries. Other major tobacco- (and alcohol)-related neoplasms also showed exceedingly high rates in Eastern Europe. For females, the highest lung cancer rates were in Scotland (29/100000), the United States (26/100000) and Denmark, reflecting the different spread of tobacco smoking in the two sexes. The highest rates for stomach cancer were in Latin America, the Russian Federation and Japan, and for colorectal cancer in the Czech Republic (37/100000 males, 20/100000 females) and Hungary. The highest breast cancer mortality rates were in Malta (30/100000 females), followed by Denmark and Britain, and for cancer of the prostate in Norway (23/100000), Switzerland and Sweden. With reference to total cancer mortality, the highest rates for males were in Hungary (262/100000), the Czech Republic (238/100000) and the Russian Federation (224/100000), and the lowest ones in Israel (127/100000), and Sweden (130/100000). In females, the highest total cancer mortality rates were in Denmark (142/100000), Scotland and Hungary, and the lowest ones in Greece (78/100000), France and Spain. These patterns of total cancer mortality for the two sexes reflect the major impact of tobacco-related neoplasms, and underline the substantial excess rates in most eastern European countries.