False‐negative errors in fine‐needle aspiration biopsy of dominant thyroid nodules: A prospective follow‐up study

Abstract

Abstract Reluctance to adopt fine‐needle aspiration (F‐NA) of dominant thyroid nodules stems largely from fear of overlooking a malignancy in a nodule diagnosed as benign on FNA (false‐negative error). Published error rates have been derived from surgical series without regard to the outcome of those who were followed without operation. In order to ascertain the overall false‐negative error rate, we conducted a prospective study in 600 patients who underwent FNA. Among the 482 study patients who had a benign FNA diagnosis or inadequate specimens, 117 underwent surgery because of the concurrent large‐needle biopsy result or a clinical suspicion of malignancy. Eight false‐negative errors were identified in this group, 5 of which were detected by large‐needle biopsy. Among the remaining 365 patients who were followed for an average of 2 1/2 years, 2 patients were found to have well‐differentiated carcinomas in recurrent cysts. The overall false‐negative error rate of FNA alone in all 482 patients was 2.1%. This was reduced to 1.0% by the use of concurrent large‐needle biopsy. Properly applied, FNA can reduce unnecessary surgery among patients with clinically benign nodules without incurring an unacceptably high false‐negative error rate. Furthermore, this error rate may be reduced substantially by combining large‐needle biopsy with FNA and by close follow‐up with surgery performed later in patients who manifest clinical features suggestive of malignancy .