Breast carcinoma in situ. Diagnostic and therapeutic aspects with special reference to growth patterns

: The probability of developing in situ carcinoma has been calculated at about 25%, while the cumulative risk of having the diagnosis established is estimated at less than 1%. In situ carcinoma in its pure form constitutes up to about 6% of all newly diagnosed breast cancers in clinical series, whereas its share in the most thorough mammographic screening series ranges from 8 to 16%. This excess in diagnosis comprises, in particular, the ductal type, primarily its most aggressive forms. To-day in situ cancer occurs chiefly as non-palpable lesions demonstrated by mammography or as minor changes discovered accidentally by the pathologist. A more recent classification based upon histological growth patterns is described. The advantage of classifying according to growth pattern bears a good correlation to clinical presentation, extent of surgery and prognosis. The treatment of in situ carcinoma lacks a rational basis. Therapy should therefore be kept within the framework of prospective protocols. Various treatment modalities are described with reference to the most important multicenter trials.