[Stereotaxic cytologic examination of non-palpable lesions of the breast. Experience with 791 consecutive cases].

The authors report on 791 consecutive cases undergoing stereotaxic cytology for nonpalpable lesions detected at mammography. Histologic diagnosis (malignant = 179, benign = 107) or mammographic follow-up after at least one year (benign = 275) was available in 561 cases. The overall inadequacy rate of stereotaxic cytology was 0.21, and dependent on lesion type (benign = 0.25, malignant = 0.13 p less than 0.001) and on sampling operator experience (range 0.17-0.31, p less than 0.001). Sensitivity (dubious + positive, after exclusion of inadequates) was 0.83 and dependent on histologic type (infiltrating = 0.87, intraductal = 0.68). Specificity (negative/benign, after exclusion of inadequates) was 0.96. Stereotaxic cytology helped in reducing the number of unnecessary benign biopsies and the biopsy ratio was 0.6 benign to 1 malignant biopsy. In cases with moderate suspicion at mammography the radiologist felt reassured by negative cytology and advised mammographic control rather than surgical biopsy. Cytology was determinant in advising surgical biopsy in 9 cancer cases whereas the absence of cytologic positivity contributed to diagnostic delay in 2 cancer cases. Overall, stereotaxic cytology allowed a relevant reduction of unnecessary benign biopsies and should be routinely employed in the diagnostic work-up of nonpalpable lesions detected at mammography.