BRAF V600E as an accurate marker to complement fine needle aspiration (FNA) cytology in the guidance of thyroid surgery in the Chinese population: evidence from over 1000 consecutive FNAs with follow-up.

BACKGROUND Currently, several commercial molecular tests have been developed for reclassifying thyroid nodules with indeterminate fine needle aspiration cytology. These tests are quite expensive and not available in China. Previous studies demonstrated a very high prevalence of the BRAF V600E mutation in Asian people. A high incidence may result in a robust sensitivity. We conducted this study to determine the prevalence of BRAF V600E mutation and its ability to reclassify cytologically indeterminate thyroid nodules in the Chinese population. METHODS Between January 2016 and October 2018, consecutive patients who underwent a fine needle aspiration procedure and agreed to provide materials for molecular analysis in our hospital were recruited in this study. All were followed up until they had a thyroidectomy and a final pathological diagnosis or until January 2019 (those did not have surgery). RESULTS A total of 1960 patients were included in this study. Until January 2019, 1240 patients underwent surgery. Using histopathological diagnosis as a gold standard, the overall sensitivity and specificity of the BRAF V600E mutational analysis for the discrimination of benign nodules from cancer in thyroid fine needle aspiration samples were 83.3% (81.0-85.3%) and 96.0% (77.7-99.8%), respectively, with an area under the ROC curve of 0.90 (95% CI 0.85-0.95, P < 0.001). Among cases with indeterminate cytology, BRAF-positive cases were showing malignancy in the final pathology, and BRAF-negative cases were showing safer to be followed up. CONCLUSION The BRAF V600E mutation is highly prevalent in the Chinese population and can accurately complement cytopathology in the guidance of thyroid surgery.Mini-abstract: The BRAF V600E mutation has both high specificity and sensitivity to predict thyroid malignancy in the Chinese population. It can accurately complement cytopathology in the guidance of thyroid surgery.