Volume of excision and cosmesis with routine cavity shave margins technique

Background. Cavity shave margin (CSM) removal is a surgical technique that reduces re-excision rates. One criticism of this technique has been that negative margins are obtained primarily as a result of higher volumes of tissue removed. This study evaluates the volume of tissue removed in a group that underwent CSM versus one that underwent standard partial mastectomy (SPM) and explores cosmetic outcomes. Methods. Single-institution retrospective review identified 533 patients with a diagnosis of breast cancer who underwent PM. Matched pair analysis of 72 patients who had undergone PM with CSM versus 72 who had undergone SPM was performed. Volumes were calculated from dimensions in the pathology report. A subgroup was analyzed by a multidisciplinary panel for cosmetic outcome using the Harvard Breast Cosmesis Grading Scale. Results. Mean tumor size in the CSM group was 1.52 versus 1.51 cm³ in the SPM (P = 0.8073). Mean total volume of tissue excised with CSM was lower than that in the SPM group. Mean volume of excision with CSM was 80.66 and 165.1 cm³ in the SPM group (P = 0.0005). Patients undergoing CSM required fewer re-excisions than the SPM group: 13 (18.1%) versus 25 (34.6%) (P = 0.03). Mean score for cosmesis was 2.3 in the CSM group and 3.0 for SPM (P = 0.0004). Conclusions. CSM decreases the need for re-excision. Total tissue volume excised is lower in patients who undergo CSM, and cosmetic results appear to be improved. This approach should be considered for all patients undergoing PM.