Resection margins in ultrasound-guided breast-conserving surgery

Few published studies have shown the benefits of intraoperative ultrasound in avoiding inadequate margins in breast-conserving surgery. The aim of this study is to quantify intraoperative ultrasound margin size and assess its relationship to tumor size, multifocality, palpability, histology, and presence of intraductal component.

Patients with breast cancer undergoing breast-conserving surgery in whom the operating surgeon visualized the tumor by ultrasound were included. Ultrasound margins measured intraoperatively were prospectively recorded and compared with pathology margins.

Forty-five patients with 48 tumors were included. Twenty five patients (56%) had palpable tumors. Pathologic mean tumor size was 1.9 cm [95% confidence interval (CI) 1.6-2.2 cm, range 0.5-4.8 cm]. There was good correlation between closest margins recorded by ultrasound and pathology margins (r = 0.4674, P < 0.0008). Fourteen patients (31%) had margins re-excised intraoperatively, 12 of them in the direction of the closest pathological margin. Three patients (7%), all of whom had intraoperative re-excision, had a second operation for involved margins without residual cancer on pathological examination of the reoperative specimens. Ultrasound margins ≥0.5 cm achieved adequate pathology margins of ≥0.2 cm in 95% of margins. Overestimation of pathology margins by ultrasound measurement was significantly affected by multifocality (P = 0.0473). Tumor size, palpability, invasive lobular histology, and presence of ductal carcinoma in situ (DCIS) did not cause significant overestimation of pathology margins by ultrasound.

Intraoperative ultrasound may help maintain a low level of reoperation after breast-conserving surgery. Ultrasound margins <0.5 cm should be re-excised intraoperatively. Reliability of ultrasound in predicting the closest pathology margins was diminished in patients with multifocal tumors.