To assess the clinical value of the abundance of BRAF^V600E mutation detected in ultrasound-guided fine needle aspiration samples in predicting cervical lymph node metastasis (LNM) of papillary thyroid carcinoma (PTC).

A total of 1046 patients with pathologically confirmed PTC between January 2020 and December 2020 at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine were collected. Ultrasound-guided fine-needle aspiration samples were collected to determine the abundance of BRAF^V600E mutation before surgery. Patients were classified into lymph node metastasis group (n=419) and no lymph node metastasis group (n=627) based on lymph node metastasis. The correlation between clinical characteristics (sex, age, tumor diameter, number of nodes, nodal location, and mutation abundance) and cervical LNM in PTC patients was analyzed using χ² test or t-test. Multifactorial analysis was performed by binary logistic regression analysis, and the diagnostic efficacy of BRAF^V600E mutation abundance in predicting cervical LNM in PTC patients was assessed by constructing receiver operating characteristic (ROC) curves.

The proportions of males, patients＜45 years old, patients with tumor maximum diameter ≥1 cm, patients with multiple nodes, and those with multiple bilateral nodes in patients with cervical LNM was significantly higher than those in patients without (32.0% vs 19.9%, 72.1% vs 54.5%, 38.9% vs 19.0%, 25.8% vs 18.0%, and 16.2% vs 10.4%; χ²=19.56, 32.62, 50.63, 9.06, and 7.78; P＜0.001,＜0.001,＜0.001, =0.003, and =0.005, respectively); the abundance of BRAF^V600E mutation was significantly higher in PTC patients with cervical LNM than in those without [(32.44±20.23)% vs (27.21±20.82) %, t=-4.29, P＜0.001]. Multifactorial regression analysis suggested that male gender, age, maximum diameter ≥1 cm, multiple nodes, and high abundance of BRAF^V600E mutation were independent risk factors for cervical LNM in PTC (OR=1.935, 0.425, 2.578, 1.651, and 2.057, respectively; P＜0.05). The sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve of BRAF^V600E mutation abundance in predicting cervical LNM were 48.69%, 65.71%, 48.69%, 65.71%, and 0.574, respectively.

The detection of BRAF^V600E mutation abundance can provide a reference for clinical decision making in cervical LNM resection in patients with PTC.