Lumpectomy cavity shaved margins do not impact re-excision rates in breast cancer patients

Background: The benefits of taking shaved cavity margins (SCM) at the time of lumpectomy are unclear. We sought to determine if taking SCM decreases re-excision rates by increasing the total breast tissue volume excised. Methods: We undertook a retrospective review of breast cancer patients who underwent lumpectomy from 2004 to 2006. Patients were divided into three groups. Group 1 had lumpectomy alone, group 2 had lumpectomy plus select (1-3) SCM, and group 3 had lumpectomy plus complete (≥4) SCM. Pathologic findings and surgical outcomes were compared between groups. Results:773 cancers treated by lumpectomy were included in this study;197 were in group 1, 130 were in group 2, and 446 were in group 3. The mean total volume of breast tissue excised in group 1 (106.6 cm ³) was significantly larger than the volume excised in groups 2 (79.3 cm ³) and 3 (76.3 cm ³). Rates of re-excision and successful breastconservation therapy (BCT) were not significantly different between groups. Despite a lower total volume of breast tissue excised in groups 2 and 3, there was no significant increase in locoregional recurrence rates (LRR) at median follow-up of 54 months. Conclusions: Taking additional SCM during lumpectomy resulted in a significantly lower overall volume of breast tissue excised, with no increase in LRR. Contrary to prior studies, we found that SCM did not decrease re-excision rates or impact the success of BCT. Therefore, the main advantage of taking SCM appears to be that less breast tissue is excised, which could potentially improve cosmetic outcomes.