Emma Huebner1, Thomas Duncan1, Javier Romero1, Graal Diaz1, Ken Waxman1 and Shawn Steen1,2*
1Division of Surgery, Ventura County Medical Center, Ventura, CA, USA
2Division of Surgical Oncology, Anacapa Surgical Associates, Ventura, CA, USA
Breast conservation surgery yields positive margin with tumor in up to two-thirds of cases, often leading to re-excision. The removal of cavity shave margins has been an attempt to decrease the rate of positive margin. In this case-controlled, age-matched study, 139 patients who underwent breast conservation therapy with or without resection of additional margins were retrospectively assigned to an Additional Margins (AM) group or No Additional Margins (NAM) group. The rates of primary specimen positive margin, tumor presence in the additional margins, and final positive margin were analyzed. Removal of shave margins in the AM group contained additional multifocal cancer in 23% cases in which the primary specimen had negative margins. Despite finding this additional disease, the rate of final positive margin in the AM group was still less than the NAM group (21% and 40%, respectively, p<0.01). Fellowship-trained breast surgeons performed 97% of the surgeries in the AM group, while general surgeons performed 57% of the surgeries in the NAM group. Thus the positive margin rates were likely biased by surgical technique. Our findings suggest that resection of additional margins may be more beneficial in identifying multifocal disease than in decreasing the rate of positive margin and re-excision.
Huebner E, Duncan T, Romero J, Diaz G, Waxman K, Steen S. Do Cavity Shave Margins Help Breast Conserving Surgery Outcomes? Clin Surg. 2019; 4: 2318.