Fine needle aspiration (FNA) cytology of the breast: the influence of unsatisfactory samples on patient management.

FNA continues to play an important role in the management of patients with breast lesions. However, the reliability and efficiency of the FNA service depends heavily on the quality of the specimens. We have audited the rate of "inadequate FNAs' at intervals over the last 5 years and related our findings to the clinical expertise of the aspirator. We have also correlated the rate of inadequate FNAs with the percentage of patients who had an FNA preceding a definitive diagnosis of cancer. We report trends in the rate of inadequate samples, and subsequent diagnosis of cancer, over a 5-year period. The percentage of breast FNA samples reported as inadequate was 46.8% in 1988-89, falling to 20% in 1991-92 with the introduction of an FNA clinic, and rising to 30.6% in 1993. The rates of cancer following inadequate FNA were 15.7%, 16.1% and 4.2%, respectively, and the percentage of patients with cancer having a preceding inadequate FNA were 37.5%, 13.2% and 7.1%. Possible explanations for the apparent paradox between increasing numbers of inadequate FNA specimens and a falling breast cancer rate are discussed.