Vacuum assisted stereotactic guided mammotome biopsies in the management of screen detected microcalcifications: experience of a large breast screening centre

Aim: To evaluate the usefulness of vacuum assisted stereotactic guided mammotome biopsy in the diagnostic management of screen detected calcifications and to rationalise its use versus diagnostic excision. Methods: The first 100 mammotome biopsies preceded by a conventional needle core biopsy (NCB) were identified from the database of Leeds/Wakefield Breast Screening Service. The histological diagnosis on NCB and mammotome were reviewed and compared with the surgical histological diagnosis if excision had been performed. Results: Using mammotome, diagnoses were changed in 74 of the 100 cases. In 66 cases a definitive diagnosis (B2 or B5) was obtained. The incidence of inadequate/unsatisfactory (B1) biopsies was reduced from 36% to 9%. In 34 cases mammotome was not helpful in arriving at a definite diagnosis (B1/B3/B4). All cases diagnosed as malignant with mammotome were proven to have in situ or invasive malignancy on excision except for one case of ductal carcinoma in situ fully excised by mammotome. There was one false negative case of in-situ carcinoma with a prior benign (B2) mammotome diagnosis. Almost half the NCB uncertain (B3) cases required excision as the mammotome biopsies were also uncertain (B3). The majority were flat epithelial atypia and atypical intraductal proliferation. Conclusions: Mammotome biopsy is particularly useful for further assessment of an inadequate (B1) or suspicious (B4) NCB diagnosis. Diagnostic surgical excision remains the method of choice for managing atypical/uncertain lesions (B3).