BRAF^V600E Combined With Ultrasonographic Features In Prediction Of Central Lymph Node Metastasis In CN0 Papillary Thyroid Microcarcinoma

ObjectiveExcessive surgical resection is the hot topic of papillary thyroid carcinoma.There are still some patients existing central lymph node metastasis of(CLNM)in clinically central lymph node negative(cN0)papillary thyroid microcarcinoma(PTMC).The preoperative diagnosis of CLNM is the key to resolve the dispute of"whether to perform prophylactic central lymph node dissection"for these patients.The purpose of our investigation is to predict the CLNM in patients with cN0 PTMC from the perspective of molecular level combined with ultrasonographic(US)features,so as to guide the selection and optimization of surgical procedures for cN0-PTMC patients.Methods and materilasA retrospective analysis was performed on 182 patients with cN0 PMTC,who underwent thyroidectomy and prophylactic central lymph node dissection from October 2015 to December 2018.The predictive risk factors for CLNM were analyzed with respect to age,sex,tumor size,tumor multiple,chronic lymphocytic thyroiditis(hashimoto thyroiditis),US features and BRAF~V600E600E analysis from US-FNA(US-guided fine-needle aspiration)biopsy.Univariate and multivariate analysis were performed to identify clinicopathological and US characteristics in predicting CLNM from PTMC.Receiver operating characteristics(ROC)curve analysis was used to evaluate the utility of markers in predicting CLNM.ResultsOf the 182 patients with cN0 PTMC,71(39.0%)were identified with CLNM by postoperative pathology.In univariate analysis,tumor size>7 mm,marked hypoechogenicity,multifocality and BRAF~V600E600E mutation were shown to be statistically significant in prediction of CLNM in PTMC.With the use of multivariate analysis,tumor size>7 mm(OR:3.636,95%CI:1.671–7.914),marked hypoechogenicity(OR:2.686,95%CI:1.080–6.678),multifocality(OR:4.184,95%CI:1.707–10.258)and BRAF~V600E600E mutation(OR:5.339,95%CI:2.529–11.272)were independent predictors of CLNM.Clinicopathological features(age,gender,chronic lymphocytic thyroiditis)and other US features(bilateral,solid component,microcalcification,irregular/lobulated margin,and non-parallel orientation)were not statistically significant with CLNM metastasis.The sensitivity was 63.4%and specificity was 80.2%,with an under the ROC curve of 0.755.ConclusionsIn conclusion,our study identified four independent predictors for CLNM in patients with cN0 PTMC:tumor size>7 mm,marked hypoechogenicity,multifocality and BRAF~V600E600E mutation,which provides a solid basis for the selection of suitable patients for prophylactic central lymph node dissection.Further validation and follow-up investigations can provide detailed guidance to the clinicians and patients.