BRAF mutation analysis by ARMS-PCR refines thyroid nodule management.

Abstract

Fine-needle aspiration (FNA) of thyroid nodules leads to nearly 25% indeterminate nodules, while BRAFV600E mutation helps to predicting papillary thyroid carcinoma (PTC). However, the clinical validity and utility of the BRAFV600E mutation detected using preoperative FNA samples in a large cohort were rarely reported. To explore the clinical significance of the BRAFV600E mutation on preoperative diagnosis and decision-making in a large FNA cohort in China. This was a prospective study of BRAFV600E mutation analysis using an amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in FNA samples. The study involved 2640 samples from 2307 patients undergoing FNA procedures in a Chinese medical centre. A high mutation rate of 86.7% was found in the PTC population. For indeterminate thyroid nodules, the malignant rate of BRAFV600E+ and BRAFV600E- was 87.8% and 39.5% in the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) III, and 88.2% and 31.8% in the BSRTC IV, respectively. A cost-effective diagnostic model combining both BSRTC grading and BRAFV600E mutation status showed the highest sensitivity of 82.9% and specificity of 85.4%. Central lymph node metastasis (CLNM) was independent of the BRAF mutation status and accounted for 34.2% of the patients with PTC. CT values of BRAFV600E of patients with PTMC were significantly lower in young patients and patients with CLNM. The combined analysis of cytological results and BRAFV600E mutation is highly recommended in BRAFV600E high-prevalence regions, including China. Prophylactic central neck dissection should be performed in selected patients without regard to the BRAF mutation status.