Breast-conserving surgery and selective adjuvant radiation therapy for stage I and II breast cancer.

In this report we update our experience with selective adjuvant radiotherapy (XRT) following breast-conserving surgery (BCS) for early breast cancer. Of 150 evaluable private breast cancer patients treated by BCS since 1975, 83 were offered the option of foregoing adjuvant XRT because their primary disease met four pathological criteria: primary tumor less than or equal to 2.5 cm; adequate resection margins; no intramammary vascular, lymphatic, or perineural invasion by tumor; and minimal or no associated in situ cancer. Of the 67 patients who chose not to have XRT, four have developed local (breast) tumour recurrence at 80 months' median follow-up (5-year local recurrence rate 6.4% by Kaplan-Meier analysis). These findings are discussed in light of other series in which patients were carefully selected for BCS without XRT, and the observations of large randomized trials and unselected series of patients. We conclude that adjuvant XRT is not always necessary following BCS. The most valuable contribution of XRT to breast-conserving therapy is that a much larger proportion of breast cancer patients can be considered for conservative locoregional surgery than would otherwise be reasonable.