A comparison of three methods for nonpalpable breast cancer excision

To evaluate the efficacy of three methods of breast-conserving surgery (BCS) for nonpalpable invasive breast cancer in obtaining adequate resection margins and volumes of resection.

A total of 201 consecutive patients undergoing BCS for nonpalpable invasive breast cancer between January 2006 and 2009 in four affiliated institutions was retrospectively analysed. Patients with pre-operatively diagnosed primary or associated ductal carcinoma in situ (DCIS), multifocal disease, or a history of breast surgery or neo-adjuvant treatment were excluded from the study. The resections were guided by wire localisation (WL), ultrasound (US), or radio-guided occult lesion localisation (ROLL). The pathology reports were reviewed to determine oncological margin status, as well as tumour and surgical specimen sizes. The optimal resection volume (ORV), defined as the spherical tumour volume with an added 1.0-cm margin, and the total resection volume (TRV), defined as the corresponding ellipsoid, were calculated. By dividing the TRV by the ORV, a calculated resection ratio (CRR) was determined to indicate the excess tissue resection.

Of all 201 excisions, 117 (58%) were guided by WL, 52 (26%) by US, and 32 (16%) by ROLL. The rate of focally positive and positive margins for invasive carcinoma was significantly lower in the US group (N = 2 (3.7%)) compared to the WL (N = 25 (21.3%)) and ROLL (N = 8 (25%)) groups (p = 0.023). The median CRRs were 3.2 (US), 2.8 (WL) and 3.8 (ROLL) (WL versus ROLL, p < 0.05), representing a median excess tissue resection of 3.1 times the optimal resection volume.

US-guided BCS for nonpalpable invasive breast cancer was more accurate than WL- and ROLL-guided surgery because it optimised the surgeon's ability to obtain adequate margins. The excision volumes were large in all excision groups, especially in the ROLL group.