In situ carcinomas of the female breast. Diagnostic and therapeutic aspects with special reference to histological growth patterns. Clinical review.

There is a disparity between the autopsy prevalence and the clinical incidence of in situ carcinoma of the breast without co-existing invasive carcinoma. The probability of developing in situ carcinoma is about 25%, while the cumulated risk of having the diagnosis established is less than 1%. In situ carcinoma in its pure form constitutes roughly 6% of all newly diagnosed breast cancers whereas in the most thorough mammographic screening series the incidence ranges from 8 to 16%. This excess in diagnosis comprises the ductal type in particular, primarily in its most aggressive forms, while the lobular type is no more common than in clinical series. Today in situ cancers occur chiefly as non-palpable lesions shown on mammography or as small changes accidentally discovered by the pathologist in a meticulous examination of an otherwise benign specimen. This survey also describes the traditional histopathological classification and presents in more detail a new classification based on histological growth patterns. The advantage of classifying in situ cancer according to its growth pattern is that it shows a good correlation with its clinical presentation. Moreover, the growth pattern can indicate the extent of excision. In addition, the method also seems to be applicable to prognosis. The treatment of in situ carcinoma has not been worked out scientifically, so treatment should be kept within the framework of prospective clinical trials. This is the only way to collect useful data about the biological behaviour of such lesions. In several countries large multicentre studies are being conducted to extend our knowledge about carcinoma in situ and to create a rational basis for treatment.(ABSTRACT TRUNCATED AT 250 WORDS)