The role of thin-needle aspiration biopsy in the diagnosis of thyroid nodules

Abstract

The paper analyzes the results of thin-needle aspiration biopsy (TNAB) performed in 1155 patients with thyroid nodules. The purpose of the paper was to evaluate the efficiency of TNAB in the differential diagnosis of thyroid nodules and in the detection of carcinoma among them. A prospective open uncontrolled study was conducted. According to the data of TNAB, benign, malignant, and suspected malignant masses were found in 808 (69.96%), 49 (4.2%), and 148 (12.8%) patients, respectively. The data of TNAB were compared with the histological findings in 333 patients undergoing surgery. The sensitivity, specificity, and other indices of the efficiency of TNAB were calculated by and without taking into account a group of suspected malignant changes. The sensitivity, specificity, and diagnostic accuracy were 93.9, 97.5, and 96.5%, respectively; the prognostic values as for the presence and absence of cancer were 93.8 and 97.5%, respectively, The presence of a group of suspected malignant changes substantially lowered the efficiency of TNAB. The specificity of TNAB in detecting thyroid cancer, assessed by taking into account this group was 52.5%; the prognostic value as to the presence of cancer was 39.8%. The diagnostic accuracy (63.2%), sensitivity (93.9%), and the prognostic value of TNAB in relation to the absence of cancer (97.5%) substantially unchanged. The presence of a rather large number of unrepresentative aspirates (13.0%), the bulk (74.7%) of which is presented by the contents of a cyst is another disadvantage of TNAB. A histological study revealed thyroid cancer in 6 out of these patients. The high (62%) incidence of cancer in the cystic nodes reasonably warrants the use of surgery in case of the repeated accumulation of the contents with a cystic node.