Effect of reexcision on the success of breast-conserving surgery.

BACKGROUND: The success of lumpectomy and radiotherapy is dependent on minimizing the residual tumor burden in the breast. Histologic margin status is one measure of the extent of residual tumor. This study was undertaken to determine the success rate of a single conservative lumpectomy in obtaining negative margins and to evaluate the incidence of residual tumor after biopsies with positive or unknown margins.
METHODS: This is a retrospective study covering a 5-year period (June 1988-June 1993).
RESULTS: Three hundred sixteen women had lumpectomies. In 239, lumpectomy was the initial operation after a positive fine-needle aspiration or as a diagnostic procedure. Thirteen cases had positive margins. Reexcision was performed in 90 cases. The indication for reexcision was a positive margin in 42 cases (4 with gross tumor) and unknown margin status in 48. Nineteen of the reexcisions for positive margins and 20 of the reexcisions for unknown margins contained residual tumor. Eighty-six (96%) of the 90 reexcised patients underwent breast preserving surgery. Patient age, menopausal status, histologic tumor type, tumor size, and clinical presentation were not predictive of residual tumor.
CONCLUSIONS: The need for reexcision does not preclude breast preservation. Because single-stage lumpectomy is successful in achieving negative margins in 95% of patients, diagnostic biopsy without margin evaluation should be abandoned to avoid routine reexcision.