[Problems of breast conservation therapy--residual cancers after lumpectomy and effects of preoperative radiotherapy].

We have investigated the effects of preoperative radiotherapy on T1 N0 breast cancer and studied the relationships between residual cancer after lumpectomy and II clinicopathological factors. Radiotherapy was basically ineffective against intraductal carcinoma. However, in the preoperative radiation group, there were more hormone-receptor positive and histologically well-differentiated cases than in the non-radiated stage I patients. Mitotic figures were also significantly reduced after radiotherapy, whereas the expression of c-erb-B-2 protein was unchanged between the two groups. Residual cancer rates were 40% and significantly higher in patients with: 1) tumor diameters of 3.1 cm or larger; 2) tumors beneath or in the vicinity of the nipple-areola; 3) malignant calcifications noted in mammography findings; 4) serous or bloody nipple discharge, particularly with positive cytologic findings; 5) papillotubular carcinoma; 6) lymphatic invasion by tumor cells; and 7) a high degree (n > or = 4) of lymph node metastases. Our date indicate the varying radiosensitivity of breast cancer cells, the indications for hormone therapy and the prognostic usefulness of these seven clinicopathological factors in breast conservation therapy.