Purpose: This study was designed to examine whether available preoperative clinical parameters, including B-type Raf kinase (BRAF) V600E mutation status, can identify patients at risk for central compartment lymph node metastasis (CLNM).
Methods: Under an institutional review board-approved protocol, we conducted a single-center, retrospective review of all patients who had initial thyroidectomy for histologic papillary thyroid carcinoma (PTC) during 2010. The presence of CLNM was examined for correlation with available preoperative clinical parameters, including tumor size, gender, age, and BRAF mutation status.
Results: Cervical lymph node resection and molecular testing on FNAB or histopathologic specimen was performed on a consecutive series of 156 study patients with histologic PTC. Overall, CLNM was diagnosed in 37% and 46% were BRAF-mutation-positive. BRAF positivity was the only clinical parameter associated with CLNM (BRAF, p=0.002; tumor size≥2 cm, p=0.16; male gender, p=0.1; age≥45 years, p=0.3) and remained an independent predictor of CLNM on multiple logistic regression analysis (odds ratio (OR) 3.2, p=0.001). The PPV and NPV of BRAF positivity for CLNM was 50 and 74%, respectively. When restricting the analysis to the subset of 38 patients who had molecular testing performed preoperatively on FNAB, the PPV and NPV of BRAF positivity for CLNM was 47 and 91%, respectively, and BRAF positivity was still a significant predictor of CLNM on both univariate (OR 8.4, p=0.01) and multivariate (OR 9.7, p=0.02) analyses.
Conclusions: Of the commonly used clinical parameters available preoperatively, the BRAF V600E mutation is the only independent predictor of CLNM in PTC and can be utilized to guide the extent of initial surgery.