[Study of conservative treatment of breast cancer in view of the spread of primary lesion].
Two hundred and six patients with breast cancer t1 or t2 were subclassified histologically into the following 8 types; comedo type, papillary type, mucous type, papillotubular or cribriform type, small solid alveolar type, large solid alveolar type, sclerotic type and pure scirrhous type. The risk of remaining cancer with lumpectomy was investigated clinicopathologically in relation to intraductal spread and lymphatic invasion of cancer cells. The tumor invasion was classified into intraductal type, localized type or extraductal spreading type, and lymphatic invasion was divided into 2 grades, i.e., vicinity of the tumor and 5mm or more distant. 1. In cases of intraductal spread, the comedo type was the most frequent, followed by the papillary type and mucous type. 2. The small solid alveolar type accounted for the highest proportion, 22.7%, in the group with distant lymphatic invasion. 3. The incidence of lymph node metastasis was as high as 63.6% and 61.7% for the small solid alveolar type and pure scirrhous type. 4. In cases of intraductal spread, t1 accounted for 32.6% and t2 for 47.0%. 5. The incidence of positive lymph node metastasis was 28.9% for t1 and 52.0% for t2. Tumors associated with a higher risk of remaining cancer are those of the comedo type and papillary type in terms of intraductal spread, those of the small solid alveolar type and pure scirrhous type in terms of lymphatic invasion, and those measuring 2cm or more.