BRAFV600E mutation is not associated with central lymph node metastasis in all patients with papillary thyroid cancer: Different histological subtypes and preoperative lymph node status should be taken into account

The association between central lymph node metastasis (LNM) and risk factors, including the presence of the BRAF mutation, BRAFV600E, in patients with papillary thyroid cancer (PTC) requires further investigation. A potent risk factor that can indicate LNM in different histological subtypes of PTC and in different preoperative central lymph node statuses also requires further research. A total of 287 patients with PTC who accepted thyroidectomy were included in the present study. Clinicopathological data of these patients were reviewed to examine the risk factors for central LNM through univariate and multivariate analyses. Overall, BRAFV600E in patients with cN0 (subclinical nodal disease) and cN1 (other than cN0) PTC was associated with central LNM. However, multivariate analyses demonstrated that BRAFV600E was not an independent risk factor in patients with cN1 or cN0 PTC. For patients with classical variant PTC (CVPTC), BRAFV600E was independently associated with central LNM. However, on further analysis, the association was only significant in patients with cN0 CVPTC. For patients with follicular variant PTC (FVPTC) or aggressive variant PTC (AVPTC), the BRAFV600E mutation rate was not significantly different between patients with and without central LNM. In conclusion, BRAFV600E was an independent risk factor for central LNM overall in patients with PTC and in patients with CVPTC, particularly in patients with cN0 CVPTC. However, BRAFV600E was not an independent risk factor for patients with FVPTC and AVPTC. Therefore, BRAFV600E provides varied clinical significance in different histological subtypes and preoperative central lymph node status.