Clinical Studies On Thyroid Fine-Needle Aspiration Diagnosis

Backgroud The popular application of high resolution ultrasound has concurrently resulted in the detection of steadily increasing numbers of asymptomatic thyroid nodules. The increasing incidence of thyroid nodules raises the need for FNA, which is more accurate than the ultrasonic inspection to determine those malignant lesions. It has been widely accepted that thyroid FNA is an invaluable tool in the evaluation of thyroid nodules. However, this technique is not often adopted in China, and there is scarce of domestic reports for clinical research of thyroid FNA in large cohorts. Thyroid FNA was performed since May2005at our hospital, which has been done independently by Endocrine physicians, not only performing but also interpreting. By August2011, there are totally2453patients with thyroid FNA. What is the value of this work, accuracy, and prospects? Those are the purpose of this study. Objectives To examine the value of thyroid FNA in management of thyroid disease and to explore the feasibility of thyroid FNA assumed and promoted by Endocrinine physicians. Methods A retrospective review of clinical and cytopathological data from2453consecutive patients who unerwent thyroid FNA from May2005to Aug.2011by Endocrine physicians of our hospital was performed.1870cases of thyroid nodule FNA,162patients who underwent FNA and subsequent thyroidectomy, and1014patients diagnosed as HT with FNA have been concluded, in comparison with large international clinical studies of thyroid FNA. Preoperative FNAs of162patients were compared with final surgical pathologic results, focusing on reasons for discrepancies between the cytological and the histological diagnosis. The sensitivity, specificity and accuracy of thyroid FNA diagnosis for identifying thyroid malignancy were evaluated by using histologic diagnosis as a gold standard. Cytopathological diagnosis was classified as six categories:non-diagnostic, benign, follicular lesion, follicular neoplasm, suspicious for malignancy, and malignant according to BSTC (The Bethesda System for Reporting Thyroid Cytopathology) Results The number of thyroid FNA has markedly increased year by year. Of1870thyroid nodule FNAs,11.4%,76.5%,1.9%,3.9%,2.0%, and4.3%were classified as non-diagnostic, benign, FL, FN, suspicious malignancy, and malignant, respectively. NG was in the first place of benign lesions accounting for48.3%, and HT was the second accounting for35.9%. PTC was in the majority (87.5%) of malignancy. The sensitivity, specificity, PPV, NPV and accuracy of thyroid FNA for the diagnosis of malignancy were98.6%,77.3%,93.3%,94.4%and93.5%, respectively. With the accumulation of experience, non-diagnostic rate declined year by year, as low as7.9%in the year of2010. Of1014HT diagnosed with FNA, thyroid autoantibody negative rate was14.1%and coexistence with PTC accounted for2.3%. Conclusions With the increase in the number of thyroid nodules being detected, the clinical needs for diagnostic procedure of thyroid FNA have markedly increased. Our6-year experiences with thyroid nodule FNA manifest that FNA has high accuracy and sensitivity for identifying thyroid malignancy, which are comparable with those of large foreign thyroid FNA studies reported recently. This method can differentiate benign and malignant thyroid nodules, and help to confirm diagnosis of HT when its clinical manifestation is not typical. Thyroid FNA is performed and interpreted independently by well trained Endocrine practitioner, providing high diagnostic accuracy rates for evaluation of thyroid nodules, which is valuable for nationalwide applications.