THE IMPORTANCE OF THE LUMPECTOMY SURGICAL MARGIN STATUS IN LONG-TERM RESULTS OF BREAST-CONSERVATION

Background. The impact of the surgical margin status an long term loca l control rates for breast cancer in women treated with lumpectomy and radiation therapy is unclear. Methods. The records of 289 women with 303 invasive breast cancers who were treated with lumpectomy and radia tion therapy from 1972 to 1992 were reviewed. The surgical margin was classified as positive (transecting the inked margin), close (less tha n or equal to 2 mm from the margin), negative, or indeterminate, based on the initial biopsy findings and reexcision specimens, as appropria te. Various clinical and pathologic factors were analyzed as potential prognostic factors for local recurrence in addition to the margin sta tus, including T classification, N classification, age, histologic fea tures, and use of adjuvant therapy, The mean follow-up was 6.25 years. Results. The actuarial probability of freedom from local recurrence f or the entire group of patients at 5 and 10 years was 94% and 87%, res pectively. The actuarial probability of local control at 10 years was 98% for those patients with negative surgical margins versus 82% for a ll others (P = 0.007). The local control rate at 10 years was 97% for patients who underwent reexcision and 84% for those who did not. Reexc ision appears to convey a local control benefit for those patients wit h close, indeterminate, or positive initial margins, when negative fin al margins are attained (P = 0.0001). Final margin status was the most significant determinant of local recurrence rates in univariate analy sis, By multivariate analysis, the final margin status and use of adju vant chemotherapy were significant prognostic factors. Conclusions. Th e attainment of negative surgical margins, initially or at the time of reexcision, is the most significant predictor of local control after breast-conserving treatment with lumpectomy and radiation therapy.