| Objective Medullary thyroid carcinoma(MTC)is uncommon,accounting for 1～2% of all thyroid cancers,arises from the neuroendocrine parafollicular C cells of the thyroid.Medullary thyroid carcinoma has few biological characteristics,which is moderate aggressive,prone to has lymph node metastasis at an early stage,does not take up iodine and a poor prognosis.The standard treatment for MTC is total thyroidectomy with prophylactic central lymph node dissection in clinically node-negative patients and therapeutic neck dissection in clinically suspicious lymph node-positive patients.As medullary thyroid carcinoma is quite rare,most papers report retrospective data and there are few studies on the regularity of cervical lymph node metastasis,the surgical management of the lateral neck compartment in patients without imaging-proven diagnosis of lateral neck disease after thorough cervical imaging and risk factors of cervical lymph node metastasis,however,is controversial.The purpose of the study was to investigate the risk factors and regularity of cervical lymph node metastasis in medullary thyroid carcinoma and determine the clinical benefits of prophylactic lateral neck dissection in clinically overt medullary thyroid carcinoma and provide indications of prophylactic lateral neck dissection.Methods 1、243 medullary thyroid carcinoma undergoing radical surgery in Tianjin Medical University Cancer Hospital from 2004 to 2017 were retrospectively collected,main data including gender,age,single or bilateral primary cancer foci,number of primary cancer foci,diameter of primary cancer foci,TNM staging,preoperative Ct etc.χ2 test and logistic test were adopted for the analysis of the risk factors of the cervical lymph node metastasis in medullary thyroid carcinoma.2、155 c N0-c N1 a patients were explored whether prophylactic lateral neck dissection improved the overall survival rate and relapse-free survival rate of clinically negative lateral lymph node imaging.Results 1.The cervical lymph node metastasis rate is 55.1% among the 243 MTC patients,the central and lateral lymph node metastasis rate was 46.9% and 43.6% respectively,the rate of skip metastasis was 8.2%,superior mediastinal lymph node metastasis rate is 8.2%,the occult metastasis rate of central lymph node and lateral cervical lymph node were 14.1 and 9.6% respectively.2.Multivariate analysis showed that the independent risk factors for central lymph node metastasis were male(P=0.003),extrathyroid invasion(P=0.012)and preoperative calcitonin >100pg/ml(P=0.01);while the independent risk factors for lateral lymph node metastasis were central lymph node metastasis(P < 0.001)and preoperative calcitonin >310pg/ml(P < 0.001).3.In the 155 patients with clinically negative cervical lymph node(c N0-c N1a)medullary thyroid carcinoma,there were no statistically significant differences in the overall survival rate,disease-free survival rate or local recurrence rate between the prophylactic lateral lymph node dissection group and the observation group.Conclusion 1.Medullary thyroid carcinoma has a incidence peak between 45 and 55 years old,the rate was equal of male to female,and is prone to lymph node metastasis,with high rate of occult and superior mediastinal lymph node metastasis.2.Male,extragalular invasion and preoperative calcitonin > 100pg/ml were the independent risk factors of central lymph node metastasis;while central lymph node metastasis and preoperative calcitonin >310pg/ml were the independent risk factors of lateral lymph node metastasis.3.For patients with central lymph node metastasis and preoperative calcitonin level >310pg/ml,prophylactic lateral neck dissection should be taken into considered. |
