Analysis Of Risk Factors Of Central Lymph Nodes Metastasis And Extrathyroidal Extension In Papillary Thyroid Microcarcinoma

ObjectiveClinicopathologic implications of papillary thyroid microcarcinoma were analyzed on central lymph node metastasis and extrathyroidal extension.And regression models were conducted to analyze the risk factors for the central lymph node metastasis and extrathyroidal extension,so as to provide appropriate operations for patients.MethodsA total of 1399 papillary thyroid microcarcinoma patients undergoing surgical treatment in Department of Thyroid Surgery,the First Affiliated Hospital of Zhengzhou University from January 2012 to September 2018 were collected and retrospectively analyzed.Risk factors for lymph node metastasis and extrathyroidal extension in central region were analyzed by multivariate logistic regression analysis and ROC curves and calibration curves were developed to test the discrimination and calibration of those two models.ResultsThere were 328 patients with central lymph nodes metastasis and 1071 patients without central lymph nodes metastasis.Univariate analysis revealed that gender(P < 0.001),age(P < 0.001),Braf V600 E gene mutation(P = 0.013),and the diameter overlarge 5mm(P < 0.001)were significantly different while associating with central lymph nodes metastasis.As for multifocality,extrathyroidal extension and coexisting with Hashimoto's thyroiditis,there was no association with central lymph node metastasis.There were 67 patients with extrathyroidal extension.Univariate analysis showed that the diameter overlarge 5mm(P < 0.001)and bilateral multifocal(P < 0.001)were significantly associated with extrathyroidal extension.Multivariate Logistic regression analysis revealed that the BRAFV600 E gene mutation(OR =1.863,95% CI 1.147~2.941,P=0.013)and the cancer diameter being overlarge 5mm(OR=2.074,95% CI 1.595~2.689,P<0.001)were the risk factors of central lymph node metastasis,and female(OR=0.585,95% CI 0.436-0.787,P<0.001)and age overlarge 55 years old(OR=0.399,95% CI0.265-0.600,P<0.001)were protect factors for the central lymph node metastasis.The diameter overlarge 5mm(OR=3.585,95% CI 1.930~6.657,P<0.001)and bilateral multifocality(OR= 2.478,95% CI 1.445~4.249,P=0.001)were the risk factors of extrathyroidal extension.After analyzing the discrimination and calibration of the two models,the AUCs of the two models were 0.65 and 0.69 according to ROC curves,and the Hosmer-Lemeshow good of fit test of these were 0.59 and 0.99.ConclusionsPapillary thyroid microcarcinoma patients with the BRAFV600 E gene mutation,the diameter overlarge 5mm and the age less than 55 years old were more likely to have central lymph node metastasis which means that it is recommended to conduct the central lymphadenectomy for the PTMC patients.If the patients were with diameter overlarge 5mm and bilateral multifocality,the risk of extrathyroidal extension is increasing.