Bilateral breast cancer in patients with initial stage I and II disease.

Between January 1947 and the end of 1975, of 2076 patients with Stages I and II breast cancer treated at M. D. Anderson Hospital, 126 received treatment for cancer in both breasts. Records of 94 patients who had only one cancer treated at U. T. M. D. Anderson Hospital and in whom staging and treatment details were not available and records of the patients who developed local, regional, or systemic failure prior to diagnosis of the second breast were excluded. Of 126 patients with bilateral breast cancer, 39 had simultaneous tumor (both cancers diagnosed within six months) and 87 had consecutive tumors. The disease-free 20-year survival rate shows no significant difference between patients with unilateral tumors and those with bilateral simultaneous or consecutive tumors. Analysis by radiotherapy modality or surgery alone shows, if anything, a lower incidence of cancer in the second breast in the irradiated patients, indicating that in patients with Stage I or Stage II lesions, the doses of radiation given in the management of the first breast cancer were not conducive to the development of a cancer in the remaining breast.