The Diagnostic Value Of Residual Fine-Needle Aspiration Needle Rinses For BRAF V600E Mutation Detection In Papillary Thyroid Carcinoma

Objective:To investigate the feasibility of detecting BRAF V600 E mutation by using residual fine-needle aspiration(FNA)needle rinses.Furthermore,to assess the diagnostic value of BRAF V600 E mutation combined with cytological diagnosis in papillary thyroid carcinoma(PTC).Methods:Cytological diagnosis and residual FNA needle rinses for BRAF V600 E mutation detection were retrospectively collected from 1674 patients,who underwent thyroid FNA in our hospital from March 2017 to December 2018.A total of 876 patients received a postoperative diagnosis.From 128 of the surgical patients,paired surgical tissue samples were collected performing BRAF V600 E mutation detection,the results of which were compared with paired residual FNA needle rinses.Results:A total of 918(54.8%)residual FNA needle rinses were identified as BRAF V600 E mutation positive.The BRAF V600 E mutation rates of different TBSRTC categories were 1.4%,4.6%,46.7%,0.0%,76.3%,and88.7%,respectively(χ2 = 792.872,P = 0.000).A total of 86.6%(733/846)PTC nodules harbored the BRAF V600 E mutation.BRAF testing identified 84.7% atypia of undetermined significance or follicular lesion of undetermined significance(AUS/FLUS)nodules and 84.4%suspicious for malignancy(SM)nodules for PTC.Cytological diagnosis exhibited a sensitivity and specificity of 83.5% and 83.7%,while the BRAF V600 E mutation status exhibited a sensitivity and specificity of86.6% and 86.4%,respectively.Combination of cytological diagnosis and BRAF V600 E mutation detection improved the sensitivity of PTC diagnosis to 97.2% and accuracy to 96.5%.128 paired residual FNA needle rinses and surgical tissues received consistent BRAF V600 E mutation results,showing almost perfect consistency(κ = 0.890,P = 0.000).Conclusion:Residual FNA needle rinses are feasible preoperative samples for BRAF V600 E mutation testing.The application of BRAF V600 E mutation testing from residual FNA needle rinses can maximize the use of limited puncture fluid to provide more diagnostic information on PTC.A combination of residual FNA needle rinses for BRAF V600 E mutation detection and cytological diagnosis can improve the sensitivity and accuracy of diagnosis of PTC,especially in patients with indeterminate cytological diagnosis(AUS/FLUS and SM).