P3-12-04: Involved Anterior Margins after Breast Conserving Surgery: Is Re-Excision Required?

Abstract

Abstract Background: Complete tumour excision in breast conserving surgery (BCS) is critical for successful treatment; involved circumferential resection margins are associated with increased disease recurrence. However, the importance of an involved anterior margin is less clear. The purpose of this study was to audit an aggressive approach to involved anterior margins and hence assess whether anterior margin re-excision yields clinical benefit. Material and Methods: A retrospective case note and pathology review was performed for all patients who underwent BCS between 2006 and 2010 through a single cancer centre. An involved margin was defined as <1mm clearance of invasive or in situ breast cancer. Results: 1667 patients underwent BCS for invasive and/or in-situ disease, of whom 114 (6.8%) underwent re-excision, most commonly for mixed invasive and in-situ pathology. The annual re-excision rate rose significantly (p<0.001), with no change in whole tumour diameter, specimen weight or specimen volume. A total of 170 involved margins were identified: most commonly the anterior margin (59 margins, 30.6%) followed by the posterior (39 22.9%) or inferior (31, 18.3%) margin. Patients with anterior margin involvement were more likely to have grade 3 invasive disease (p=0.0323) but less likely to have residual disease found at re-excision (2/49 vs. 32/101 margins, p=0.0033); there were no differences when in-situ characteristics were compared. Conclusions: Re-excision of involved anterior margins rarely excises residual disease and may be unnecessary. Multidisciplinary teams should consider whether further therapy for an involved anterior margin is required on a patient by patient basis. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-12-04.