[Reevaluation of the histological classification of breast cancer--a presentation of a new histological classification considering the relationship between scirrhous tendency and postoperative prognosis].

The present study was designed to evaluate the correlation between the histology and the prognosis of the patients with breast cancer. In this study, 1271 cases with breast cancer were retrospectively studied and an attempt of a new histological classification was presented, which was intended to reflect the prognosis more exactly than the ordinarily used classification by Japan Mammary Cancer Society. Japan Mammary Cancer Society classifies infiltrating carcinoma into 3 types; papillotubular, medullary tubular and scirrhous carcinoma. In this study, when scirrhous interstitial infiltration was observed in papillotubular or medullary tubular carcinoma, even if scirrhous tendency was observed only in small part, the patients' prognosis was as poor as scirrhous carcinoma. The prognosis of common type of infiltrating carcinoma with scirrhous tendency corresponded to that of one grade advanced stage without scirrhous tendency. Considering these results and clinical usefulness, common type of infiltrating carcinoma should be classified to 2 types, namely with or without scirrhous tendency in order to reflect the prognosis and to correspond to WHO classification.