A Comparison Of Fine-Needle Aspiration Versus Non- Aspiration Cytology Of Thyroid Nodules

Background Fine needle aspiration (FNA) is considered the investigation of choice in cytological sampling of thyroid nodules. Non-aspiration fine needle cytology (NAC) has been described as an alternative method with technical and interpretive advantages. This study compares the sampling adequacy and diagnostic accuracy of NAC with FNA in predicting neoplasia and malignancy in thyroid nodules. Methods Patients presenting to a single surgeon with a thyroid nodule had both NAC and FNA performed. Both NAC and FNA specimens of all those who had subsequent thyroid resection were retrospectively graded and correlated with the histological diagnosis to determine rates of adequacy and diagnostic accuracy. Results Both NAC and FNA plus surgical resection were performed on 65 thyroid nodules. NAC produced less inadequate specimens (26%) than FNA (37%). Combining both techniques reduced the inadequacy rate to 20%. In predicting malignancy, FNA and NAC were equally sensitive (89%) but FNA had higher specificity (66 v 54%) and accuracy (71 v 60%). In predicting neoplasia, FNA again had higher specificity (90 v 77%) and accuracy (85 v 79%) but sensitivity rates were similar (81 v 81%). Conclusion NAC is a technically simple method of sampling thyroid nodules and appears to produce more adequate specimens. It has similar sensitivity to FNA in predicting neoplasia and therefore surgery. However, FNA appears to have better overall accuracy. In order to maximise yield it may be appropriate to use both sampling methods in the cytological investigation of thyroid nodules.