Cavity Shaving for Invasive Breast Cancer Conservative Surgery: Reduced Specimen Volume and Margin Positive Rates.

Introduction: The cavity shaving (CS) technique was described in breast conserving surgery to reduce the rate of reoperation avoiding the need for intraoperative margin analysis. This study assesses differences in the rates of involvement of the surgical margin (requiring further surgery) and volume of surgical specimens, depending on the use or not of this technique. Material and methods: A retrospective cohort study was conducted in patients with breast carcinoma who underwent breast conserving surgery between 2013 and 2019. They were divided into two groups depending on whether the cavity shaving technique was used or not. Primary outcomes of the study included presence of final margin involvement, requiring need for further surgery, and the volume of excised tissue comparing the study groups. Results: A total of 202 cases were included: 92 in the control group and 110 in the cavity shaving group. Significant differences were found regarding involvement of the final margin (19.57% control group vs. 4.55% cavity shaving group; p = 0.010). The volume of additional surgical specimens were significantly greater in the traditional technique group than in the shaving technique (46.43 vs 13.32 cm3; p = 0.01) as was total specimen volume (143.40 vs 100.63 cm3; p = 0.022). Conclusions: CS can reduce the positive margin and re-excision rates without larger-volume resections and should therefore be considered a routine technique in BCS for early-stage breast cancer.