Data Material, Methods and Organization of Sections

Mortality and Incidence

Briefly, this new edition of the Cancer Atlas describes the temporal progression of cancer mortality in Germany from the early 1950s to 1995 and its geographic distribution during the period 1981-1990 for 24 types of cancer and for cancer as a whole. Viewing the mortality rates for malignant neoplasms is of interest in itself, since the high fatality of these diseases reflects their severity and their relevance to public health policy.

But the recent decline in cancer mortality, even among males, highlights the fact that mortality covers only one aspect of the disease process, i.e., the cases that have a tatal outcome. As a result, the more treatable forms of cancer (e.g., skin cancer) may be unrepresented in an atlas of cancer mortality. Meanwhile, we may see a decline in deaths from cancers that were usually fatal in the past but now are diagnosed and treated with a much higher degree of success. This decline in mortality does not necessarily mean that the risk of contracting a particular cancer is reduced. In extreme cases the risk (incidence) of the disease may even continue to rise while its mortality falls, illustrating how mortality statistics can portray only one part of the complete picture.

Finally, declining mortality from a disease may reflect the elimination or disappearance of risk factors for the disease; as the incidence declines, there will necessarily be an associated decrease in mortality. Because it is not readily apparent simply from a decline of mortality (e.g., the recent decline in males) whether this decline is based on a falling incidence or on improved diagnosis and treatment combined with a potentially rising incidence, one can appreciate the urgency of establishing complete, nationwide cancer registration to provide a comprehensive description of the "cancer landscape."

Nationwide cancer registration has been practiced in the eastern part of Germany since 1961. These records enable us to appreciate long-term and recent secular trends and geographic patterns (see Möhner et al. 1994), so they help to complete our portrait of the cancer landscape. In the past, there were only two regions in western Germany that maintained cancer registries: Hamburg and the Saarland. As these areas represented a mere 5% of the total West German population, epidemiologists were unable to obtain accurate incidence numbers (annual numbers of new cases) for western Germany. In early 1995, however, new legislation was enacted for the purpose of instituting complete, nationwide cancer registration for all of Germany.

Because of confidentiality rules that restrict the reporting of medical data, the cancer detection rate in the Hamburg registry has declined markedly during the past few years. As a result, the comparative incidence figures cited in certain sections of this atlas are based entirely on the cancer registries of the Saarland and the former GDR. Meanwhile, these data have been used to make order-of-magnitude extrapolations on disease incidence for the German population as a whole, and these projections are utilized in the text. Details on these data sources are presented below.

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