Predictors of margin status after breast-conserving operations in an underscreened population.

PURPOSE: Negative margins after lumpectomy remain a prominent issue in breast surgery. The current study was performed to evaluate patient-related variables that affect risk for positive margins in an underscreened population.
METHODS: A retrospective review was performed of all patients who underwent breast-conserving operations from 2001 to 2010. Sociodemographic, clinical, and treatment variables were evaluated. One millimeter from tumor to inked margin was considered a negative margin. Univariate and multivariate analyses were performed to identify variables which affect margin status after a lumpectomy.
RESULTS: Over the time period evaluated, 69 patients had positive margins (31 %) and 155 (69 %) had negative margins. Overall use of screening mammography was poor (36 %). In unadjusted analysis, patients with positive margins were less likely to have undergone screening mammography (p = 0.003) and presented with a palpable mass (p = 0.01). Histopathologic variables which predicted increased risk for positive margins included larger pathologic size, greater number of pathologically involved lymph nodes, higher pathologic stage, presence of lymphovascular invasion (LVI) and extensive intraductal component (EIC), p < 0.05. In multivariate analysis, clinical stage, poor histologic grade, LVI, and EIC were associated with positive margins (p < 0.05). By contrast, use of preoperative chemotherapy was associated with attaining negative margins (p < 0.05).
CONCLUSIONS: Factors associated with positive margins after lumpectomy included poor histologic grade, LVI, and EIC. Use of preoperative chemotherapy was the strongest independent predictor of lower risk for positive margins.