An audit of detailed margin assessment in breast conserving surgery specimens supports the routine use of shaved radial margins

Abstract

Aim The status of excision margins is a well recognised predictive factor for likelihood of recurrence following breast conserving surgery (BCS). Radial margins may be examined by perpendicular sections or shaving. The aim of this audit was to determine what, if any, additional information shave margins provide. Methods Three hundred consecutive BCS specimens were reviewed, with shave margins having been performed in 209. Histological involvement of radial and shave margins for invasive carcinoma, ductal carcinoma in situ and pleomorphic lobular carcinoma in situ was recorded, as were findings in any further re-excision specimens. Results In 13% of cases shave margins only were positive, and 57% of these cases had residual invasive or in situ disease in re-excision specimens. In 8% of cases where both the radial and shave margins were involved, the positive shave margin was different to the radial and would have led to a more extensive re-excision. Therefore shave margins gave additional information to clinicians and impacted on surgical management in 21% of cases. Conclusions Shave margins from BCS specimens appear to identify margin involvement in an increased proportion of patients who would otherwise be left with residual disease. We suggest that these findings support the routine use of shave margins despite current Royal College of Pathologists of Australasia (RCPA) recommendations.