Extent of Margin Involvement, Lymphovascular Invasion, and Extensive Intraductal Component Predict for Residual Disease After Wide Local Excision for Breast Cancer

BackgroundPositive margins after wide local excision (WLE) increase the probability of residual disease, and additional surgery is often recommended. However, residual tumor will be found in only two thirds of cases, suggesting that additional surgery can be avoided in many instances. In the present study, we sought to establish the frequency of residual tumor when the surgical margins are inadequate and to identify factors that predict for residual tumor.Materials and MethodsA retrospective review was performed of 720 consecutive patients who had undergone WLE for ductal carcinoma in situ and nonmetastatic breast cancer at a single unit from January 1, 2004 to December 31, 2010.ResultsAt least a single radial margin was affected (either involved or close, defined as tumor < 1 mm from the margin) in 244 patients who had undergone WLE, and either the anterior or posterior margin was affected in another 103 patients. Reoperation was performed in 215 patients with affected radial margins and 9 others with affected anterior or posterior margins. Residual disease was found in 98 of 224 patients (43.8%) and was more likely when tumor was present at the inked margin, when > 1 radial margin was affected, and when lymphovascular invasion (LVI) or an extensive intraductal component (EIC) was present. The association with tumor size was of borderline significance. No association was found with tumor histologic type or patient age.ConclusionAdditional evaluation is needed to determine whether additional surgery can be safely omitted in women with tumors without LVI or EIC when a single radial margin has been deemed to be close.