The effect of simultaneous peripheral excision in breast conservation upon margin status.

Abstract

Negative margins in breast conservation therapy (BCT) decrease local recurrence risk. Excision may be performed via two techniques: either as a single lumpectomy specimen or as a central segment with simultaneously resected peripheral segments (PSs). There is little data directly comparing these methods for their effect on margin status. A retrospective review of all patients undergoing BCT for invasive breast cancer was conducted to evaluate and compare the two techniques. Presentation, pathologic characteristics, surgical technique, specimen volume, and final margin status were recorded. Among 259 cancers in 257 women, 33 had positive margins. A single segment was removed in 69 patients, while 190 patients had 1-6 PSs simultaneously removed. By univariate analysis, smaller tumor size (P = .017) and greater numbers of segments removed (P = .01) lowered the risk of positive margins. In a multivariate model, smaller tumor size (P = .0024), lack of EIC (P = .049), and greater numbers of segments removed (P = .0061) lowered the risk of margin positivity. Despite this last predictor, the total resected specimen volume did not increase with the number of PSs removed (P = .4). There was no residual tumor in 49.2% of PSs despite a compromised primary segment margin. Smaller tumor size, lack of EIC, and greater numbers of simultaneous PSs excised decrease the likelihood of positive margins, despite a lack of correlation between segment numbers and excised volume. These findings suggest that excision of simultaneous PSs may assist in achieving negative margins, in part, because of avoidance of pathologic artifact.