Stereotaxic needle-core biopsy and fine-needle aspiration biopsy in the diagnosis of nonpalpable breast lesions: controversies and future prospects.

OBJECTIVE: To determine the advantages and limitations of a combined stereotaxic fine-needle aspiration biopsy and needle-core biopsy in the diagnosis of 353 nonpalpable breast lesions with special attention given to the collection of follow-up data. METHODS AND MATERIAL: 353 nonpalpable breast lesions underwent 'one pass' stereotaxic fine-needle aspiration (21 gauge needle) and needle-core biopsy (18 gauge needle) at our institution from January 1990 to October 1993. Stereotaxic biopsies were carried out by means of an 'add-on unit'. Surgical biopsy was usually recommended for highly suspicious radiologic patterns and/or needle biopsy reports classified as atypical or malignant. In all other cases mammographic follow-up was advised at 6 months and then annually for 3 years. The data were collected retrospectively during September 1995 (theoretical average follow-up of greater than 3 years).
RESULTS: Following the combined needle biopsy technique procedure, surgery was recommended for 83 lesions. Fifty-four cancers were associated to these suspicious lesions. Because of changing radiological or clinical pattern during follow-up (mean follow-up: 22 months), 11 cancers were detected among the 270 lesions initially considered not to need surgery. Forty-three percent of the 65 malignant lesions were initially read as having less than highly suspicious mammographic features. There was no significant difference between the sensitivity and the specificity of one pass fine-needle aspiration biopsy (57% and 96% respectively) and needle-core biopsy (60% and 97% respectively), but noncontributive samples were not included in the false negative diagnoses and atypical samples were included in the true positive diagnoses. Of the 11 missed cancers, nine were manifested initially by clusters of calcifications. Our diagnostic approach was significantly less sensitive (P = 0.006) and less specific (P = 0.032) in cases of clusters of calcifications (31% false negative diagnoses) than in cases of soft-tissue masses (5.5% false negative diagnoses). In this study, an average delay in diagnoses of 22 months was responsible for a significantly increased percentage of axillary node positive invasive cancer (P < 0.001) and six of the 11 missed cancers were palpable at the time of the delayed diagnosis. For the nine cancers initially manifested by calcifications, the 22 months delay in diagnosis was responsible for a nonsignificant increase of microinvasive type at the expense of carcinoma in situ.
CONCLUSION: Our enthusiasm with the sensitivity of this double stereotaxic needle sampling has been tempered by the results of this reanalysis in the light of a mean theoretical follow-up of three years. Our diagnostic approach was adequate in the presence of soft-tissue masses but not valid in the presence of clustered calcifications. When dealing with calcifications, multiple samplings must be done in order to improve the sensitivity of the diagnosis. Furthermore, this study does not favour the theory that the majority of mammographically detected cancers are indolent and highlights the poor sensitivity of the mammographic follow-up of nonpalpable lesions.