Three hundred fifty-six patients with early (Stage I and II) breast cancer and 55 with advanced (Stage III and IV) breast cancer were treated between 1979 and 1985 with a consistent policy of breast conservation irrespective of tumor site, size, or histologic features. Only three patients underwent primary mastectomy (Stage III), and the remainder were treated either by wide local excision and postoperative radiotherapy (357 cases) or by needle biopsy and primary irradiation (51 cases). A total of seven of 356 (2%) Stage I and II patients have developed uncontrolled local or nodal recurrence at a median follow-up of 5 years, and nine of 55 (16%) of Stage III and IV patients. Of the 62 Stage I and II patients who have died, seven (11%) have died with uncontrolled locoregional disease. Of the 22 Stage III and IV patients who have died, eight (36%) have died with uncontrolled locoregional disease. Although the majority of local recurrences within the conserved breast could be salvaged by secondary surgery (37/38 Stage I and II patients), the development of chest wall or nodal recurrence was usually associated with the appearance of distant metastases and a poor prognosis. Data on uncontrolled local recurrence should be given in all studies of breast cancer treatment, since it represents an important end-point of therapy and a difficult clinical problem.