Background: The most common diagnostic procedure in the United States for mammographically detected nonpalpable lesions is a combination of a vacuum-assisted biopsy device and a prone-type biopsy table. We have used an upright-type stereotactic mammography unit without a digital imaging system instead of the prone table.
Patients and methods: Five-hundred ten biopsies of 506 mammographically detected nonpalpable breast lesions in 488 patients, consisting of 445 lesions with microcalcifications alone, 39 masses without calcifications, and 22 with both masses and microcalcifications, were attempted using a combination of a vacuum-assisted device (Mammotome) and an upright unit without a digital imaging system in a sitting position between May 1999 and February 2007.
Results: Breast tissue was obtained in 497 biopsies. Microcalcifications were confirmed radiographically in the tissue of 447 out of 459 biopsies from lesions with microcalcifications (97.4 %). One hundred thirty-seven were diagnosed as malignant, 10 as atypical ductal hyperplasia, 345 as benign, and 1 was not diagnosable. The underestimation rate was 28.0 %. Overall, 26 patients (5.1 %) had vasovagal reactions, while 19 (3.8 %) experienced mild subcutaneous bleeding. Two hundred fifty of 350 lesions, for which biopsy diagnoses were benign, were followed for a median period of 33 months. Four lesions turned out to be malignant. The false-negative rate was 2.8 %.
Conclusion: The biopsy technique using the combination of the Mammotome and an upright unit without a digital imaging system is cost-effective, safe, and accurate, and should be regarded as one of the standard biopsy methods for mammographically detected nonpalpable lesions.