[Regional distribution of stomach and colon cancer mortality in the Dithmarschen and Nordfriesland districts--cartographic presentation].

In two counties (Dithmarschen and Nordfriesland) of the Federal State of Schleswig-Holstein (in the northern part of Germany) the cancer mortality rates, especially those of stomach and colon cancer, were evaluated for the time period 1980-1991. For this purpose the corresponding death certificates collected in these counties were analysed. The counties were subdivided into 16 and 17 smaller areas, respectively. The age-adjusted mortality rates were calculated and the obtained data scaled into eight sections, which were graphically mapped over the smaller areas of the two counties. The frequency of these cancer mortality rates reflects a wide range of distribution pattern in the smaller areas of the two counties, which greatly differ from the cancer mortality values calculated for the two counties as a whole. In comparison with the frequency of stomach cancer mortality for men published in the German Cancer Atlas in 1984 it could be demonstrated that this cancer mortality further decreased in these counties. However, in some smaller areas of these counties, especially in rural areas, the mortality rates of stomach cancer in men were still rather high. The opposite seems to be reflected regarding the frequency of colon cancer mortality. Here higher frequencies of mortality were seen in the small cities of these counties. We suggest that a more subtile cancer mortality mapping can be performed easily without any risk of hurting the requirements of personal data securities, because cancer mortality data are already continuously evaluated by a trained staff at the offices of statistical affairs. These data may be transferred and used for cancer mortality mapping as described in the present paper. In order to guarantee that there will be no violation of personal data secrecy the cancer mortality mapping must be restricted to cancer sites with high frequencies of mortality. All published data should be supervised by an official with special knowledge of the requirements of personal data protection. This study underlines the necessity for higher resolution (smaller areas) in cancer registries as essential prerequisite for systematical exploration of the origins of cancer mortality and as a basis for preventive measures.