Ultrasound-guided breast-conserving surgery for early-stage palpable and nonpalpable invasive breast cancer: decreased excision volume at unchanged tumor-free resection margin

Ultrasound guidance (USG) during breast-conserving surgery improves tumor-free surgical resection margins. The objective of this study was to evaluate whether USG reduces resection volumes without compromising margin status. 134 patients with palpable or nonpalpable T1-2N0-1 invasive breast cancer were treated with USG and compared with a historical reference control group (CON) consisting of palpation-guided (PAG) or wire-guided localization (WIG) breast-conserving surgery. Primary outcomes were excess resection volume and clear margin status, and secondary outcome was re-excision rate. 66 patients underwent USG. In the CON group (n = 68), PAG was performed in 24 (35 %) and WIG in 44 (64 %) patients. Median excision volume [39 (IQR 20-66) vs 56 (38-94) cm(3); p = 0.001] and median calculated resection ratio [1.7 (1.0-2.9) vs 2.8 (1.4-4.6) (p = 0.005)] were significantly smaller in the USG than in the CON group. Median minimal distance to the resection margin [4 mm (IQR 2-5 mm) vs 2 mm (1-4 mm), p = 0.004] was significantly larger. Clear resection margins were achieved in 58 of the USG patients (88 %) and in 58 of the CON patients (86 %) (p = 0.91); this was true in patients with palpable as well as nonpalpable lesions. Reexcision was needed in 6.1 and 7.2 % respectively. Relative risk for re-excision in the USG group was 0.82 (95 % CI 0.23-2.93). In patients with palpable and nonpalpable breast cancers, USG allows for lower excision volume and reduced resection of healthy breast tissue, without increased re-excision rate.