Shirin Sioshansi, M.D., from the UMass Memorial Medical Center in Worcester, and colleagues examined the risk of residual carcinoma after lumpectomy and its correlation with pathologic factors, including molecular phenotype, in pathologic specimens from 369 women (median age, 57 years) with invasive breast cancer.

The researchers found that 32 percent of patients had invasive cancer in their reexcision specimens, with residual invasive disease on reexcision seen in 51 percent of those with TN cancer, compared with 30 to 31 percent for other subtypes. An increased risk of residual invasive cancer correlated with age, tumor size, margin status, lymphovascular invasion, nodal status, and TN subtype, on univariate analysis. TN subtype remained significant in a multivariate analysis (odds ratio, 3.28).

"Our study shows that TN phenotype is independently correlated with increased risk of residual disease after lumpectomy," the authors write. "This finding suggests that TN breast cancers harbor more microscopic residual disease after lumpectomy, and thus molecular phenotype should factor into decision-making regarding the extent of initial surgery (generous gross margins) and the need for reexcision."

Abstract
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