Resection of Cavity Shave Margins in Stage 0–III Breast Cancer Patients Undergoing Breast Conserving Surgery

Abstract

Objective: Single-center studies have demonstrated that resection of cavity shave margins (CSM) halves the rate of positive margins and re-excision in breast cancer patients undergoing partial mastectomy (PM). We sought to determine if these findings were externally generalizable across practice settings. Methods: In this multicenter randomized controlled trial occurring in 9 centers across the United States, stage 0–III breast cancer patients undergoing PM were randomly assigned to either have resection of CSM (“shave” group) or not (“no shave” group). Randomization occurred intraoperatively, after the surgeon had completed their standard PM. Primary outcome measures were positive margin and re-excision rates. Results: Between July 28, 2016 and April 13, 2018, 400 patients were enrolled in this trial. Four patients (2 in each arm) did not meet inclusion criteria after randomization, leaving 396 patients for analysis: 196 in the “shave” group and 200 to the “no shave” group. Median patient age was 65 years (range; 29–94). Groups were well matched at baseline for demographic and clinicopathologic factors. Prior to randomization, positive margin rates were similar in the “shave” and “no shave” groups (76/196 (38.8%) vs. 72/200 (36.0%), respectively, P = 0.604). After randomization, those in the “shave” group were significantly less likely than those in the “no shave” group to have positive margins (19/196 (9.7%) vs. 72/200 (36.0%), P < 0.001), and to require re-excision or mastectomy for margin clearance (17/196 (8.7%) vs. 47/200 (23.5%), P < 0.001). Conclusion: Resection of CSM significantly reduces positive margin and re-excision rates in patients undergoing PM.

Impact of systematic cavity shave margins in breast‐conserving surgery at a large community hospital with a low baseline re‐excision rate

“…This decision influences the amount of tissue a surgeon takes during original BCS. In studies by Dupont and colleagues 11 and Chapgar and colleagues 2 with intraoperative randomization, systematic CSM resulted in a larger total volume of tissue excised; in our study, without intraoperative randomization, the volume of tissue excised in the no shave margins and systematic CSM groups did not differ.…”

“…A study by Dupont et al indicated a reduction in positive margin rate from 18.5% in the no shave group to 5.8% in the shave group in a subgroup analysis of three surgeons with positive margin rates less than 25% prior to randomization 11 . However, in this study, as well as in the study by Chapgar and colleagues, 2 randomization occurred intraoperatively after the surgeon had taken what was felt to be an adequate specimen.…”

“…Future studies can address the discrepancy between the literature with baseline high re‐excision rates and the much lower national average re‐excision rate to ensure generalizability and confirm that the effect is significant in populations with lower re‐excision rates. The work by Dupont and colleagues 11 is a step in the right direction; however, more work is needed to assess whether differences in volume of tissue excised explain the previously shown decreases in re‐excision rate with systematic CSM. Another area deserving added study is the low concordance between CNB and final pathology with regard to the presence of DCIS.…”

Intraoperative ultrasonography‐guided surgery: An effective modality for breast conservation after neo‐adjuvant chemotherapy

“…43 Besides, several other studies pointed out CS as an effective technique to avoid re-excisions in the adjuvant setting. 44,45 However, data about upfront systemic therapy are limited to retrospective cohort series, reporting the status of CS as the only independent predictive factor for loco-regional recurrence after NAC. 46 In accordance, IOUS successfully ruled out margin positivity in all patients in our protocol where CS is a routine and no-ink-on-tumor is regarded as safe margin after NAC.…”

“…Landercasper et al reported surgeon performed US, NAC, and CSs as the actionable processes to decrease reoperations after BCS 43 . Besides, several other studies pointed out CS as an effective technique to avoid re‐excisions in the adjuvant setting 44,45 . However, data about upfront systemic therapy are limited to retrospective cohort series, reporting the status of CS as the only independent predictive factor for loco‐regional recurrence after NAC 46 .…”