It isaweil known fact that the earlier the illness is recognized and treatment initiated, the better are the results of cancer therapy. The demand for earllest possible treatment generated the necessity for development of methods for the diagnosis of the earliest forms of cancer. A search for the smallest cancer thus started, leading to the recognition of epithelial changesthat were undoubtedly abnormal, although their malignant nature was dubious. The long interval before a true malignant tumor develops, according to observations made by various groups of investigators all over the globe, rendered the malignant nature of the primary epithelial change unlikely. In the search for the smallest cancer, its precursor was found. It thus became possible to interrupt the chain of changes leading to cancer, through less extensive surgical intervention, before the develop ment of the typical destructive form. Nowhere is this sequence of events more obvious than in cancer of the uterine cervix. The easy access to these tumors made the applications of the systematically developed ingenious methods of search especially successful. Only classical histo logic examination, however, can form the basis for the correct evaluation of these methods. A great number of early changes associated with cervical cancer were dis covered in recent years in Cologne through the clever application of methods for early detection. These cases represent the basis of the work of the Köln-Bonn team with regard to the morphology and classification of carcinoma in situ.weiterlesen