The first publication of cancer mortality data in Po- ners, research workers and political authorities for land took place 100 years ago in 1888. The evalua- information on frequencies, time trends, and spatial tion of such data was greatly enhanced in the early distributions of the different cancer sites. 1960s when the Polish Cancer Registry was estab- Secondly, it may promote epidemiological research lished at the Maria Sldodowska-Curie Memorial on causal factors determining cancer occurrence in Cancer Institute in Warszawa. Data from this regis- Poland. In this connection, it has to be kept in mind try and their epidemiological analysis provided the that the presentation of geographical distribution of basis for planning cancer control in Poland. The diseases cannot by itself provide evidence for any National Cancer Programme permitted a develop- speculations on causal relationships. Cancer map- ment of comprehensive cancer centres and cancer ping offers a valuable basis for obtaining new in- research. sights and creating new hypotheses. The proof will Differences in cancer incidence and mortality ob- have to be left to the more refined research meth- served in various regions of Poland have been eval- ods of modem epidemiology, which is also pursued uated during the past two decades using data col- at our institutes.