Thyroid cytological examination by using fine needle aspiration biopsy combined with BRAF gene testing: its diagnostic value in differentiating benign from malignant thyroid nodules / 介入放射学杂志

ABSTRACT

Objective To evaluate the combination use of thyroid fine needle aspiration biopsy (FNAB)and V-Raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E gene mutation testing in differentiating benign from malignant thyroid nodules.Methods A total of 64 patients with pathologically-proved thyroid nodules were included in this study.The clinical data,including preoperative ultrasound-guided thyroid FNAB and BRAF V600E gene mutation detection,were retrospectively analyzed.Taking postoperative histopathological results as diagnostic gold standard for the thyroid nodule,the diagnostic values of simple FNAB,simple BRAF V600E gene mutation testing,and combination use of FNAB and BRAF V600E gene mutation detection were separately assessed.Results In the 62 patients a total of 64 nodules were detected (2 patients having bilateral nodules) and treated with surgery.Of the 64 nodules,BRAF V600E mutation was detected in 44 nodules,and 43 nodules were proved to be thyroid papillary carcinoma by postoperative pathological examination.Among the 44 nodules showing BRAF V600E mutation,FNAB made malignant diagnosis in 28,benign diagnosis in 6,and uncertain diagnosis in 10.Of the 20 nodules showing no BRAF V600E mutation,FNAB made malignant diagnosis in 5,benign diagnosis in 3,and uncertain diagnosis in 12.The postoperative pathological examination confirmed that 14 lesions were thyroid papillary carcinoma,4lesions were nodular goiter,one lesion was subacute thyroiditis,and one lesion was thyroid adenoma.Among the 57 thyroid papillary carcinomas,BRAF V600E mutation was detected in 43,with the mutation rate being 75.4％.Compared with the gold standard based on pathological diagnosis,the sensitivity,specificity,positive predictive value,negative predictive value,correct diagnosis rate of FNAB for judging benign or malignant thyroid nodules were 78.9％,85.7％,97.8％,33.3％ and 79.7％ respectively,which of BRAF V600E gene mutation detection for judging benign or malignant thyroid nodules were 75.4％,85.7％,97.7％,30.0％ and 76.6％ respectively,and which of FNAB plus BRAF V600E gene mutation detection for judging benign or malignant thyroid nodules were 94.7％,71.4％,96.4％,62.5％ and 92.2％ respectively.By using McNemar paired data x2 test to compare FNAB with combination use of FNAB plus BRAF V600E gene mutation detection in diagnosing thyroid nodules,the results indicated that statistically significant deference in differentiating benign from malignant thyroid nodules existed between the two methods (P＜0.001).Conclusion For the qualitative diagnosis of thyroid nodules which nature cannot be determined by simple FNAB,FNAB combined with BRAF V600E gene mutation detection can improve the diagnostic accuracy for benign and malignant thyroid nodules.