Management Of Sporadic Medullary Thyroid Carcinoma With Negative Lateral Lymph Node Imaging

ObjectiveMedullary thyroid carcinoma(MTC)is a special type of neuroendocrine neoplasm.Malignant proliferation and abnormal differentiation of parafollicular cells(C cells)are the basis of its pathological changes,which are caused by mutations in the proto-oncogene RET.In addition,the correlation between microRNA and the occurrence of medullary thyroid cancer has also been proved in recent years.The main clinical manifestations were carcinoid syndrome such as diarrhea and flushing,which lacked specificity.According to the characteristics of the disease,MTC can be divided into sporadic medullary thyroid carcinoma(SMTC)and hereditary(HMTC).According to the combination of different tumors,HMTC can be divided into multiple endocrine neoplasia type 2A(MEN2A),multiple endocrine neopl(2B).Asia type 2B,MEN2B)and familial medullary thyroid carcinoma(FMTC).In diagnosis,calcitonin(CTN)and carcinoembryonic antigen(CEA)are the most valuable serum indicators.The final diagnosis should be based on the typical histological morphology as the gold standard.The biological characteristics of MTC are relatively special,which is moderate malignant,easy to recur and metastasis,poor prognosis,and poor effect of radiotherapy and chemotherapy.Radical surgery is the most effective treatment for early localized MTC.So far,there is still much controversy about whether to perform selective lateral neck dissection(ELND)in the case of negative imaging of lateral lymph nodes.This paper retrospectively analyzed the clinical and pathological data of SMTC patients in our hospital,and explored whether ELND for sporadic medullary thyroid carcinoma(SMTC)with negative lateral lymph node imaging had an impact on biological cure,local recurrence,final disease outcome and distant metastasis,so as to provide relevant basis for rational surgical treatment.MethodsFrom January 2007 to December 2018,56 cases of sporadic medullary thyroid carcinoma with negative imaging upper lateral lymph nodes were retrospectively analyzed.The patients with MTC with negative imaging of lateral lymph nodes were divided into two groups according to different surgical methods:non-ELND(observation group)and unilateral or bilateral ELND(ELND group).Relapse,distant metastasis and the outcome of the final disease are different.Results56 patients met the inclusion criteria:32 patients in the observation group(57%)and 24 patients in the ELND group(43%).Three of the 32 patients in the observation group(9%)had subsequent lateral lymph node metastasis.During the last follow-up,the local disease control rates in the observation group and ELND group were 94%and 92%(P=0.765),while the biochemical cure rates were 84%and 63%(P=0.117),and the local recurrence rates were 9%and 13%(P=0.708),respectively.ConclusionsThe patients in the observation group and ELND group had a similar result of biochemical cure,local recurrence,distant metastasis and final disease.Preventive ELND is not recommended in MTC patients with negative lateral lymph node imaging.