Nonpalpable breast lesions: stereotaxic fine-needle aspiration cytology.

The authors reviewed the accuracy of stereotaxic fine-needle aspiration cytology in prediction of the presence of cancer. Seventy-four nonpalpable breast cancers and 144 benign lesions were studied. The rate of obtaining an inadequate sample was 8.1% for cancers and 20.8% for benign lesions. None of the cytology reports were false-positive, whereas the accuracy of cytologic atypia in prediction of cancer was 72%. Sensitivity and specificity after 1 year of follow-up were 83.8% and 96.6%, respectively, with atypia reports being assumed positive. In patients strongly suspected of having cancer at mammography, the decision to perform biopsy must be independent of the cytologic report, as false-negative cytologic findings are expected. In patients with a low suspicion at mammography, abnormal cytologic findings were the determining factor for a request for biopsy of six cancers and of two benign lesions. Negative cytologic results contributed to the recommendation of follow-up of two lesions that turned out to be malignant. At the authors' institution, the benign-to-malignant biopsy ratio of nonpalpable lesions was greatly reduced after stereotaxic cytologic study became available; the rate of detection of subclinical cancer remained almost unaffected.