Abstract INTRODUCTION: Taking routine cavity shave margins (CSM) reduces positive margin and re-excision rates by 50%, but the impact of this technique on operative time and overall costs have not been well-elucidated. METHODS: The SHAVE trial randomized 235 Stage 0-3 breast cancer patients undergoing partial mastectomy 1:1 to either have further cavity shave margins resected ("shave") or not ("no shave"). Randomization occurred intraoperatively after surgeons had completed standard partial mastectomy. Intraoperative time as well as actual direct costs incurred by the hospital were measured, for both the index case as well as any surgeries over the subsequent 90 days. RESULTS: Median patient age was 61 (range; 33-94). 54 patients (23%) had invasive cancer, 45 (19%) had DCIS, and 125 (53%) had both. Median invasive tumor size was 1.1 cm (range; 0-6.5), and median DCIS size was 1.0 cm (range; 0-9.3). The "shave" and "no shave" groups were well-matched in terms of baseline characteristics, including the proportion having a sentinel node biopsy (75.6% vs. 69.8%, p=0.32) and/or axillary node dissection (9.2% vs. 7.8%, p=0.68) at the time of the initial surgery. The median number of additional CSM in the "shave" group was 4 (range; 3-6). At the initial surgery, those in the "shave" group had a longer operative time (median 76 vs. 66 minutes, p=0.005), and higher OR, pathology and total costs (see table). 48 patients required a subsequent surgery; 45 (93.8%) for margin clearance, 3 for sentinel lymph node biopsy alone (2 in the "shave" and 1 in the "no shave" group, p=1.00). There was a significantly lower re-excision rate for margins in the "shave" group (10.9% vs. 27.6%, p=0.001). Median time to re-excision was 22 days (range; 10-62). The mean cost of additional surgeries for those who required them was no different between the "shave" and "no shave" groups ($2636 vs. $3453, p=0.12); however, given the overall lower reoperation rate in the "shave" group (12.6% vs. 28.4%, p=0.003), the mean cost per patient for additional surgeries was significantly lower in the "shave" vs. "no shave" group. Taking into account all surgeries (including the index case and any additional surgeries within 90 days), there was no significant difference in cost (from a hospital perspective) between the two groups. Mean (± SE) Costs per patient"Shave" (n=119)"No Shave" (n=116)p-valueIndex surgery: OR costs$1315 (± $69)$1138 (± $52)0.042Pathology costs$1195 (± $43)$795 (± $48)< 0.001Total costs$4758 (± $123)$4133 (± $119)< 0.001Additional surgery: OR costs$94 (± $24)$247 (± $44)0.003Pathology costs$51 (± $18)$112 (± $21)0.031Total costs$332 (± $88)$983 (± $189)0.002Total 90 day surgery costs: OR costs$1409 (± $76)$1385 (± $64)0.808Pathology costs$1247 (± $49)$909 (± $52)< 0.001Total costs$5090 (± $166)$5116 (± $214)0.925 CONCLUSIONS: Taking routine CSM is associated with increased time and cost for the index surgery, but this is offset by the cost savings of reduced re-excision rates. While the strategies of "shave" and "no shave" are similar in terms of 90 day hospital-related costs, taking CSM is associated with a lower need for reoperative surgery, thereby reducing patient angst and improving utilization of surgeon and OR time. Citation Format: Chagpar AB, Longley PB, Horowitz NR, Killelea BK, Tsangaris TN, Li F, Butler M, Stavris K, Yao X, Harigopal M, Bossuyt V, Lannin DR, Pusztai L, Loftus M, Davidoff AJ, Gross CP. Impact of routine cavity shave margins on time and money: Results from the SHAVE trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-13-01.
