The treatment of potentially curable carcinoma of the breast has changed from one operation, radical mastectomy, to a flexible approach. At the Cleveland Clinic, we use four types of treatment for primary potentially curable carcinoma of the breast (Stages 0, I and II)--modified radical mastectomy, simple mastectomy, partial mastectomy with postoperative adjuvant radiation therapy and partial mastectomy without radiation therapy. The latter treatment (partial mastectomy without adjuvant radiation) is controversial. We recommend this procedure for patients with T(is) and T1 carcinomas that appear to be localized, without lymph node metastases, Stages 0 and I disease. The overall and disease-free survival rates are similar to those of patients having modified radical or partial mastectomy with radiation. Local recurrence is slightly higher at five years (11.0 percent) as compared with the other procedures, but at ten years, is only 16.1 percent, a figure comparable with patients having partial mastectomy with radiation (14.4 percent). For patients with Stages 0 and I carcinoma of the breast, the addition of postoperative radiation therapy after partial mastectomy seems to be unnecessary.