• We describe 111 patients with invasive breast cancer treated by segmental mastectomy at the University of Miami (Fla) since 1975. Postoperative adjuvant radiotherapy was recommended as optional rather than mandatory to 64 of these patients based on small (2.5 cm or less) primary tumor size, adequate resection margins, no lymphatic or vascular invasion within the segmental mastectomy specimen, and minimal associated in situ cancer. Fifty-one of these patients elected to forego postoperative adjuvant radiotherapy. At 72 months median follow-up, relapse occurred in the ipsilateral breast in three patients who elected to forego postoperative adjuvant radiotherapy (6% by Kaplan-Meier analysis). Retrospective pathologic review revealed that tumor grade may also be important in determining whether postoperative adjuvant radiotherapy is necessary following segmental mastectomy. These data suggest that postoperative adjuvant radiotherapy may not be required in every patient treated by segmental mastectomy. Further studies to define which patients can be spared the inconvenience, expense, and potential morbidity of postoperative adjuvant radiotherapy are warranted.
(Arch Surg. 1990;125:364-369)