FINE-NEEDLE ASPIRATION OF THYROID-NODULES - DETERMINANTS OF INSUFFICIENCY RATE AND MALIGNANCY YIELD AT THYROIDECTOMY

OBJECTIVE: To evaluate patient- and practice-specific determinants of the thyroid nodule fine needle aspiration (FNA) insufficiency rate and malignancy yield at a tertiary-care teaching hospital. STUDY DESIGN: All FNAs of thyroid nodules performed from August 1990 to October 1993 at the Walter Reed Army Medical Center Endocrinology Clinic were revi ewed and the results analyzed for correlation with surgical outcome, s cintiscanning result and operator experience. Provider-specific factor s influencing the FNA insufficiency rate, surgical referral pattern an d malignancy yield were evaluated. RESULTS: A total of 504 aspirations in 422 patients with thyroid nodules were included in the analysis. T he sensitivity of FNA for detecting malignancy was 80%, specificity wa s 73.2%, and accuracy was 75.2%. A significant negative correlation wa s found between recent aspirator experience and the insufficiency rate . Repeat aspiration of nodules previously yielding benign cytology inc reased the malignancy yield. Surgical excision of nodules with insuffi cient aspirations gave a low malignancy yield, and aspiration of nodul es that were ''hot'' on scintiscanning rarely yielded false positive F NA results. CONCLUSION: Specific limitations of thyroid nodule FNA inc lude a large number of aspirates containing insufficient cytologic mat erial and a variable malignancy yield. Specific recommendations based on the findings in this report are: the establishment of uniform crite ria for judging specimen adequacy, the performance of repent aspiratio n on thyroid nodules with previously benign aspirates, the abandonment of scintiscanning in the routine management of thyroid nodules and a conservative approach to clinically indolent nodules repeatedly found to have scant cellularity on FNA. Based on these findings, an algorith m for the diagnostic evaluation of a solid thyroid nodule can be const ructed.