Correlation between US-FNAC with BRAF V600E Mutation Analysis and Central Neck Lymph Node Metastasis in cN0 Papillary Thyroid Cancer

Abstract

The aim of this study was to explore the correlation between ultrasound-guided fine-needle aspiration cytology(US-FNAC) combined with BRAF V600E mutation analysis and central neck lymph node metastasis in cN0 papillary thyroid cancer, so as to provide reliable molecular evidence to use it for preoperative evaluation, operation procedure design, and postoperative follow-up planning in clinic. Specimens were obtained from 250 patients with cN0 thyroid cancer (TI-RADS≥4a, highly suspected of PTC by US-FNAC) after bilateral thyroidectomy and central neck lymph node dissection with accessible postoperative pathologic results of PTC and central neck lymph nodes and used for cytological diagnosis by H&E stain and BRAF V600E mutation detection. Single-factor analysis showed that differences between the central neck lymph node metastasis and nonmetastasis groups were statistically significant in gender, BRAF V600E mutation, and extracapsular extension. Logistic multivariate regression analysis showed significant differences in gender, BRAF V600E mutation, and extracapsular extension. Positive BRAF V600E mutations by US-FNAC, extracapsular extension, and male gender are risk factors of central neck lymph node metastasis in cN0 PTC metastatic PTC to central neck lymph node. Patients with those factors should undergo prophylactic central neck lymph node dissection.

Figure 1

PTC ultrasonic image: the lesion manifests hypoecho, clear margin, inner microcalcification, a height-to-width ratio > 1, and extracapsular invasion.

Figure 2

Negative results of US-FNAC combined with BRAF V600E mutation by PCR (no mutation).

Figure 3

Positive results of US-FNAC combined with BRAF V600E mutation by PCR (see mutation site indicated by the arrow).