A prospective study of 25 cases of primary carcinoma of the breast was established. The patients were treated by radical mastectomy and lymphadenectomy followed by chemotherapy with Vincristin, Adriblastin and Endoxan. No radiotherapy was employed. During a 12 month follow-up, no patient, had recurrence or progression of the tumor. It is too early to evaluate the treatment definitively regarding survival and definite value of the method. The theoretical and experimental considerations for ancillary chemotherapy are discussed.