Stereotaxic localization and core needle biopsy of nonpalpable breast lesions: two-year follow-up of a prospective study.

In August 1989, we began a prospective study of patients with abnormal mammograms to determine the clinical efficacy of stereotaxic localization and needle biopsy of nonpalpable breast lesions. By August 1990, 115 patients had undergone stereotaxic localization and needle biopsy of nonpalpable breast lesions using the Mammotest II (Fischer Imaging, Denver, CO) and an 18-gauge needle in a Bard Biopty gun (Bard Urological, Covington, GA). In 19 per cent (22 of 115) of the cases, the pathologist suggested open surgical biopsies of the lesions due to clinical judgment, or atypical or cancer cells in the core biopsy specimen. Of these 22 cases, 12 (54%) were found to be cancer on open surgical biopsy--10 per cent of all the patients. Of the remaining 93 patients with benign pathology, 9 were lost to follow-up by the end of the second year after closure of the study. The remaining 84 patients were followed by mammography and physical exam at 3 months, at 12 months, and yearly thereafter to determine whether cancer had been missed or developed at the biopsy site. The median follow-up was 24 months (mean, 23.3 months), and all 84 patients were found to have no evidence of malignant disease at follow-up. The small group (10 cases) of patients who were determined to have benign disease by open surgical biopsy were also found on follow-up to have no evidence of malignant disease (median follow-up, 20.5 months; and mean, 18.3 months). The accuracy of this stereotaxic procedure, combined with an approximately 80 per cent decrease in the more expensive and more invasive open surgical biopsy procedure, provides strong support for the use of this procedure on all nonpalpable breast lesions that would normally proceed to open surgical biopsy.