Excising Additional Margins at Initial Breast-Conserving Surgery (BCS) Reduces the Need for Re-excision in a Predominantly African American Population: A Report of a Randomized Prospective Study in a Public Hospital.

Background: Margin status is an important prognostic factor for local recurrence after breast conserving surgery (BCS) for breast cancer. We designed a prospective randomized trial to evaluate the effect of shave margins on positive margins and locoregional recurrence (LRR).

Methods: Patients were randomized to BCS or BCS with resection of 5 additional margins (BCS + M). Tumor margins were classified as negative [>2 mm for ductal carcinoma in situ (DCIS); >1 mm for invasive carcinoma] based on guidelines at the time of accrual.

Results: A total of 75 patients with stage 0-III breast cancer (76 samples) were randomized, mean age 59.6 years with median follow-up 39.5 months. Overall, 21 patients (27.6 %) had positive margins: 14 had undergone BCS and 7 BCS + M (p = 0.005). Of the 21 patients with positive margins, 19 had DCIS on final pathology (OR 7.56; 95 % CI 1.52-37.51).All patients with positive margins were offered re-excision; 11 had negative final margins after re-excision surgery. Overall, 6 patients (8.3 %) developed LRR with recurrence being more common in the BCS group when compared with the BCS + M group (17.2 vs 2.3 %; p = 0.025).

Conclusions: Taking additional cavity shave margins at the time of initial excision resulted in a reduction in positive margin rate, a decrease in return to operating room for re-excision, and lower LRR.