The Effects of Additional Tumor Cavity Sampling at the Time of Breast-Conserving Surgery on Final Margin Status, Volume of Resection, and Pathologist Workload

Margin status is an important prognostic factor for local recurrence after breast-conserving surgery (BCS) in patients with breast malignancy. It is unclear whether the removal of additional tumor cavity margins reduces the reoperation rate and is cosmetically acceptable. This study compares the reoperation rates, volume of breast excised in cm(3), and number of pathology slides examined in two groups of patients who underwent BCS with or without four or five additional margins (BCS + M). We retrospectively analyzed 320 patients who underwent BCS or BCS + M for stage 0-I-II breast cancer from 2004 to 2007. We classified the margins as negative (a parts per thousand yen1 mm), close (< 1 mm), or positive based on the distance from the tumor to the margin of resection. Of 320 cases analyzed, 199 (62.2%) underwent BCS and 121 (37.8%) had BCS + M. Overall, patients with BCS + M had a higher negative margins rate (85.1% vs. 57.2%, P < 0.05) and a lower reoperation rate. However, when ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDC) were analyzed separately, only patients with IDC showed a higher negative margin rate (91% vs. 62.1%, P < 0.001) and a lower volume of breast tissue excised (205.63 vs. 392.27, P = 0.03). There was no significant increase in pathology workload in both groups. Resection of four to five additional margins during BCS for early-stage invasive breast cancer results in a higher rate of negative microscopic margins, lower volume of breast excised, and subsequently, a lower reoperation rate. The advantages of this approach include improved patient satisfaction and decreased cost.