Epidemiological features of biliary tract cancer incidence in Slovakia.

This descriptive study is based on detailed data of biliary tract cancer incidence in Slovakia in the period 1968-1977. Age-adjusted incidence rates of biliary tract cancer in the given decade decreased in females while in males they showed a slight increase. The study of geographic distribution revealed diminishing incidence rates from west to the east in both sexes with extremely elevated rates in towns and suburban districts in males. Different shapes of age-specific incidence curves together with the identified histological types suggested different epidemiological characteristics of individual subsites within this site. Relatively high incidence rates of biliary tract cancer in Slovakia as well as in whole Czechoslovakia, in comparison with other countries or areas of Europe, could be related to the excessive prevalence of gallstones and high number of surgical interventions upon biliary tract in this country while the decreasing incidence rates in women coincided with elevated number of cholecystectomies. The significance of detailed descriptive data from cancer registries for further analytic and etiologic study of biliary tract cancer according to subsites for a better delimitation of high risk groups and primary prevention strategies is stressed.