THE NUMBER OF POSITIVE MARGINS INFLUENCES THE OUTCOME OF WOMEN TREATED WITH BREAST PRESERVATION FOR EARLY-STAGE BREAST-CARCINOMA

BACKGROUND. There are conflicting reports regarding whether focally po sitive surgical margins influence tumor control in breast-conservation therapy. The authors have evaluated the relation between positive sur gical margins on tumor control and whether the number of positive marg ins affects tumor control in patients undergoing reexcision lumpectomy . METHODS. From 1978 to 1994, 453 American Joint Committee on Cancer S tage I/II breast carcinoma patients were treated at Thomas Jefferson U niversity Hospital with breast conservation therapy. Patients underwen t excisional biopsy and margin sampling with shaved biopsies of the tu mor cavity. The entire breast received 45 grays (Gy) with a 20-Gy irid ium-192 implant or an electron boost. Eighty-six patients had microsco pically positive margins (19%), and the remainder had confirmed negati ve margins. The median follow-up time was 45 months. RESULTS. Local tu mor control rates for patients with negative margins at 5 and 10 years were 94% and 87%, respectively, compared with 86% and 69%, respective ly, for those patients with positive margins (P = 0.005). The disease free survival rates for the negative margin group at 5 and 10 Fears we re 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%, re spectively, compared with 87% and 78% respectively, for those with pos itive margins (P = 0.047). When comparing the negative margin group wi th the one positive margin group, there was no significant difference in local tumor control (P = 0.12). However, women with two or more pos itive margins had an inferior local tumor control compared with those women with negative margins (P = 0.002). CONCLUSIONS. Patients with po sitive margins have a higher risk for local failure and worse survival when undergoing breast conservation therapy. Inferior local tumor con trol was noted in those patients with two or more positive margins. (C ) 1998 American Cancer Society.