The number of positive margins influences the outcome of women treated with breast preservation for early stage breast carcinoma

Abstract

There are conflicting reports regarding whether focally positive surgical margins influence tumor control in breast-conservation therapy. The authors have evaluated the relation between positive surgical margins on tumor control and whether the number of positive margins affects tumor control in patients undergoing reexcision lumpectomy. From 1978 to 1994, 453 American Joint Committee on Cancer Stage I/II breast carcinoma patients were treated at Thomas Jefferson University Hospital with breast conservation therapy. Patients underwent excisional biopsy and margin sampling with shaved biopsies of the tumor cavity. The entire breast received 45 grays (Gy) with a 20-Gy iridium-192 implant or an electron boost. Eighty-six patients had microscopically positive margins (19%), and the remainder had confirmed negative margins. The median follow-up time was 45 months. Local tumor control rates for patients with negative margins at 5 and 10 years were 94% and 87%, respectively, compared with 86% and 69%, respectively, for those patients with positive margins (P=0.005). The disease free survival rates for the negative margin group at 5 and 10 years were 91% and 82%, respectively, compared with 76% and 71%, respectively, for the positive margin group (P=0.001). Overall survival rates for patients with negative margins at 5 and 10 years were 95% and 84%, respectively, compared with 87% and 78%, respectively, for those with positive margins (P=0.047). When comparing the negative margin group with the one positive margin group, there was no significant difference in local tumor control (P=0.12). However, women with two or more positive margins had an inferior local tumor control compared with those women with negative margins (P=0.002). Patients with positive margins have a higher risk for local failure and worse survival when undergoing breast conservation therapy. Inferior local tumor control was noted in those patients with two or more positive margins.