Diagnostic role of cytology in screen-detected breast cancer.

Fine-needle aspiration cytology (FNAC) of the breast was performed in 491 patients over a 3-year period. Some 365 examinations (74.3 percent) were performed by palpation and the remaining 126 (25.7 percent) by stereotaxis. Ninety-six patients were excluded because of inadequate follow-up. Using a standard method of reporting the results 247 smears were classified as C1 and C2, but based on clinical and radiological criteria excision biopsy was recommended and performed in 122 patients with these lesions. Twenty-two per cent of C2 lesions were found to be malignant after histological examination. Forty-two patients with C3 or C4 cytology were advised to have excision biopsy and 41 had surgery. In all but one case the lesion was found to be malignant histologically. Definitive surgery was performed on 106 patients with C5 cytology and the diagnosis of malignancy was confirmed histologically in 105 of them. FNAC is a useful diagnostic tool in breast screening but in view of the number of false-negative results, cytology alone is unreliable and, therefore, full triple assessment is recommended.