Mansmann et al have detailed impressively of how the process quality of an early detection (screening) program can be described comprehensively and transparently by using carefully collected data. In their article, however, the authors remind us of the importance of "comprehensive evaluation of colonoscopy as a tool for preventing colorectal carcinoma"—that means an evaluation of outcome quality of the results. This request has to be linked to the use of epidemiological cancer registries, which include all the necessary, high quality data that are required for the evaluation of end points (e.g. mortality).
In contrast to mammography screening, quality assurance and evaluation in colorectal cancer screening are not linked to the cancer registries. The authors are therefore forced to exclude a crucial quality indicator of screening programs—namely, the interval cancer rate. Even statements about the population related effects of colonoscopy—such as changes in the incidence of and mortality due to colorectal cancer in participants and non-participants, or the evaluation of the distribution of tumor stages in the target population—cannot be made without including the cancer registries into the screening program (which is common practice in the international setting).
With regard to these issues, colorectal cancer screening should in future use as its orientation point the evaluation of mammography screening.