Predictors of Residual Disease in Repeat Excisions for Lumpectomies with Margins Less Than 0.1 cm

Abstract

Purpose This study sought to identify factors that would predict the presence of residual disease (RD) in repeat-excision specimens following an initial breast-sparing excision procedure in which the margins of resection were free of tumor but in which tumor was very close to ≥ 1 margins. Patients and Methods Ninety-one lumpectomies with close but not transected margins and their subsequent repeat-excision specimens were analyzed for tumor type near margin in the primary excision, presence of RD, type of RD, stage of infiltrating carcinoma (IC) in the primary excision, extent of ductal carcinoma in situ (DCIS), and grade of IC and/or DCIS. Results Nineteen of 91 patients had DCIS only; 15 had IC only; and 57 had IC with DCIS in their primary excisions. Thirty-five cases (38%) contained RD in their subsequent repeat-excision specimens. Residual DCIS and/or IC was present in 58% of patients whose primary tumors were DCIS only or invasive carcinoma < 6 mm (T1a), whereas invasive carcinomas ≥ 6 mm had RD in only 28%. Twenty-three patients (64%) with extensive DCIS had RD, whereas 12 patients (22%) with no DCIS or minor DCIS (< 10 mm) had RD (χ 2 = 16.27; P < 0.001). Ductal carcinoma in situ was within 0.1 cm of the margin in 52 patients, and RD was present in 26 (50%), whereas 18 of 56 patients (32%) with IC close to the margin had RD ( P < 0.05). Grade of DCIS and IC was not related to presence of RD. Residual carcinoma was present in 38% of repeat-excision specimens with close but not transected margins in this study. Conclusion The extent of DCIS in the primary specimen, DCIS near ≥ 1 margins, and size of infiltrating tumor were related to the presence of RD.