Stereotactic vacuum-assisted breast biopsy in 268 nonpalpable lesions

We evaluated the reliability of stereotactic vacuum-assisted breast biopsies (VAB) from our personal experience.

Between January 2003 and December 2005, 268 patients underwent VAB with an 11-gauge probe at our institution. Inclusion criteria were nonpalpable lesions, undetectable by ultrasound and suspected at mammography (microcalcifications, circumscribed mass, architectural distortion), for which cytology and/or core biopsy could not provide a definite diagnosis. Lesion mammographic patterns were microcalcifications in 186 cases (77.5%), mostly localised clusters (130/186: 70%); circumscribed mass with or without microcalcifications in 36 cases (15%) and architectural distortion with or without microcalcifications in 18 cases (7.5%). On the basis of the Breast Imaging Reporting and Data System (BI-RADS) classification, 16 cases (7%) were graded as highly suspicious for malignancy (BI-RADS 5), 81 (34%) as suspicious for malignancy (BI-RADS 4b), 97 (40%) as indeterminate (BI-RADS 4a) and 46 (19%) as probably benign (BI-RADS 3). Lesion size was 20 mm in only 38 cases (16%), 30 of which appeared as microcalcifications.

In 28/268 lesions (10.5%) the biopsy could not be performed (nonidentification of the lesion; inaccessibility due to location or breast size). In 12/240 (5%) biopsies, the sample was not representative. Pathology revealed 100/240 (42%) malignant or borderline lesions and 140/240 (58%) benign lesions. Among the malignant lesions, 16/100 (16%) were invasive carcinoma [infiltrating ductal carcinoma (IDC) or infiltrating lobular carcinoma (ILC)], 13/100 (13%) were microinvasive (T1mic), 35/100 (35%) were ductal carcinoma in situ (DCIS), 9/100 (9%) were lobular carcinoma in situ (CLIS). Among the borderline lesions, 27/100 (27%) were atypical epithelial hyperplasia [atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH)]. In 9/100 surgically treated lesions (9%), there was discordance between the microhistological findings of VAB and the pathological results of the surgical procedure: 8/9 were underestimated by VAB (four ADH vs. DCIS, three DCIS vs. IDC, one ADH vs. IDC), and 1/9 was overestimated (T1mic vs. DCIS). Complications following VAB occurred in 9/240 patients (3.7%).

In our experience, VAB showed fair reliability in the diagnosis of nonpalpable breast lesions despite a portion of failed (10.5%), nonsignificant (5%) procedures and underestimated lesions (9%).