STEREOTAXIC FINE-NEEDLE ASPIRATION CYTOLOGY OF NONPALPABLE BREAST-LESIONS - INITIAL EXPERIENCE IN A TERTIARY-CARE INSTITUTION

To assess the accuracy of stereotactic fine-needle aspiration cytology in the diagnosis of nonpalpable breast lesions, this procedure was performed in 226 consecutive patients, all women, immediately before needle localization and excision of the lesions. The patients were treated at a tertiary-care hospital between December 1989 and October 1991. The cytologic results (lesion benign, atypical, suspicious or malignant or insufficient material for interpretation) were compared with the histologic findings and the degree of suspicion (low, slight or high) on the basis of mammographic examination. The aspiration procedures were successful in only 159 patients (70.4%), and for 155 of these, histologic findings were available for correlation. The number of unsatisfactory specimens in this group was large: 65 of 155 (42%). When unsatisfactory specimens were included in the calculations and a cytologic finding of a suspicious or malignant lesion was treated as positive, the sensitivity of fine-needle aspiration cytology for malignancy was 23% (8/35) and the specificity 53% (63/120). The positive and negative predictive values were 89% (8/9) and 78% (63/81) respectively. A cytologic finding that the lesion was benign was unreliable in lesions for which the mammographic suspicion of malignancy was slight or high (4 of 30 malignant lesions with slight mammographic suspicion and 4 of 7 with high mammographic suspicion were classified as benign on the basis of the cytologic examination). Of the 24 cases with atypical cytologic findings, 10 involved malignancy. The positive and negative predictive values were better when the mammographic degree of suspicion and the cytologic results were combined: for the 20 patients with low suspicion and benign cytologic findings, the negative predictive value was 100%, and for the 7 patients with high suspicion and positive cytologic findings, the positive predictive value was also 100%. The technical limitations of the technique, the large number of unsatisfactory specimens and the suboptimal diagnostic accuracy limited the diagnostic benefit of fine-needle aspiration cytology at the authors' institution. If this method is to be used, it should be performed with meticulous attention to technique and careful assessment of the results.