Therapy of primary breast cancer.

Most breast cancers are multicentric in origin. They drain into two primary lymphatic depots-the axilla and internal mammary chain of nodes. The incidence of metastasis to the internal mammary nodes rises as the location of the primary tumor approaches to the sternal margin of the breast. One hundred and thirty-seven patients primarily with in situ and non-infiltrating intraductal carcinoma were treated adequately by simple mastectomy and axillary dissection with preservation of the pectoral muscles. All have remained free of disease. Infiltrating cancers arising in the lateral portion of the breast are best treated by radical mastectomy since they spread mainly to the axillary nodes. Medial and central infiltrating cancers have been treated by radical mastectomy with internal mammary resection, since they show a higher incidence of internal mammary metastasis. Seventy-two percent of 500 patients treated in this fashion survived at five years and 65 percent were clinically free of disease. A five-year salvage rate of 60 percent and a ten-year salvage rate of 50 percent were obtained in patients with only internal mammary node metastasis or in those with only axillary involvement. When both nodal areas were involved 43 percent remained free of disease at five years and 20 percent at ten years. Mammography and biopsy of the contralateral breast at the time of radical mastectomy contributed to the detection of early localized breast cancer.