Positive or close margins in breast conserving surgery: Is re-excision always necessary?

BackgroundMore than half of re-excision specimens after breast conserving surgery (BCS) are found to be free of residual tumor at definitive histology. The aim of this study was to identify clinicopathological factors along with intrinsic subtypes of the tumor (luminal A, luminal B, HER2-overexpressing, triple-negative) associated with residual tumor in re-excision or mastectomy specimen.MethodsTwo hundred forty-eight patients with initial BCS, who underwent one or more re-excisions or mastectomy because of close or positive margins were reviewed.ResultsResidual cancer was found in 50% of re-excision(s) or mastectomy specimens. Patients with multifocality (vs unifocality; OR = 5.2; 95% CI, 2.6–10.4) or positive nodes (vs negative nodes; OR = 2.5; 95% CI, 1.4–4.4), or positive margins (vs close margins; OR = 1.7; 95% CI = 1.0–2.9) were more likely to have residual tumor in re-excision or mastectomy specimen compared to others.ConclusionOur results suggest that further surgery is often indicated in patients with node positive or multifocal cancers or positive margins after BCS since residual disease cannot be ruled out. Re-excision or mastectomy could be omitted in patients with close margins with favorable factors such unifocal tumor or node negative disease.