The Value Of Detection Of BRAFV600E Combined With Cytodiagnosis In Qualitative Diagnosis Of TI-RADS4 Thyroid Nodules

Objective:To evaluate the value of detection of BRAF V600E combined with cytodiagnosis in qualitative diagnosis of thyroid nodules(TNs)classified as thyroid imaging-reporting and data system(TI-RADS)4,and to improve the accuracy of preoperative diagnosis of TNs.Methods:We reviewed the clinical data of TNs TI-RADS 4 that underwent ultrasound-guided fine needle aspiration biopsy(US-FNAB)and detection of BRAFV600E during Jul.2019 to Sept.2020 in our hospital,and followed up the results of cytology,molecular biology and histopathology.According to the Bethesda system for reporting thyroid cytopathology(BSRTC),TNs were divided into group A(explicit diagnosis)and group B(unclear diagnosis).Histopathological results were regarded as the gold standard.We calculated the accuracy,sensitivity,specificity.The consistency between different examination results and histopathological results was analyzed by kappa test.Comparisons between US-FNAB and US-FNAB+BRAFV600E were made using theχ~2-test.Results:There were 720 TNs that underwent US-FNAB and detection of BRAFV600E.Among them,321 cases were treated by surgery,and histopathological results showed that 290 cases were malignant and 31 cases were benign.There were 235 nodules with BRAFV600E mutation and 86 nodules without BRAFV600E mutation.The results of cytological examination were 3 cases of Bethesda class I,9 cases of class II,3 cases of class III,27 cases of class IV,243 cases of class V and 7 cases of class VI.In group A,the accuracy of the detection of BRAFV600E was 82.0%,the sensitivity was 80.2%,the specificity was 100%,andκ=0.430(±0.059).The accuracy of US-FNAB was94.5%,the sensitivity was 94.7%,the specificity was 92.6%,andκ=0.727(±0.064).The accuracy of US-FNAB+BRAF V600E was 98.3%,the sensitivity was 98.9%,the specificity was 92.6%,andκ=0.900(±0.044),excellent agreement was observed.We compared the diagnostic accuracy,sensitivity,and specificity of US-FNAB and US-FNAB+BRAF V600E,P<0.05,and the difference was statistically significant.In group B,66.7%of Bethesda class I nodules carried BRAFV600E,85.2%of Bethesda class III nodules carried BRAFV600E,and no Bethesda class IV nodules carried BRAFV600E.BRAFV600E mutation occurred in 25 nodules,and all of them were papillary thyroid cancer(PTC).Conclusion:Adding BRAFV600E gene detection in the process of US-FNAB,the accuracy can be improved by the combined diagnosis for the TNs with clear cytological diagnosis,and malignant nodules can be screened by the results of the detection of BRAFV600E for those with vague diagnosis.US-FNAB combined with BRAFV600E gene detection can improve the efficiency of qualitative diagnosis of TI-RADS 4thyroid nodules.