[Experiences with early diagnosis of colon and rectum carcinomas in West Germany--epidemiological viewpoint].

In the framework of a nationwide screening for cancer in the Federal Republic of Germany, the digital rectal examination has been paid for by legal health insurance since 1974 and the fecal occult blood test since 1977. In view of the cost involved, attempts at an evaluation ought to be made despite the lack of necessary documentation for direct linkage of participation with outcome. Two national registries show rising incidence already beginning at age 40 for both tumour sites, whereas since 1977 the mortality rates in the whole Republic for rectal cancer began to decline. A similar effect became apparent for colon cancer mortality in 1979 for both sexes. The discrepancy between low participation rates in the age groups with the most substantial decline of mortality makes it hard to reason that it was a direct effect of the screening, especially in the light of a theoretical estimation of no effect on overall mortality considering the sensitivity of the screening test, in-depth follow-up examination, lethality with and without screening and a predictive value of the test of five percent. It appears, therefore, imperative to improve the evaluation, if necessary by case-referent studies.