Clinical Characteristics And Prognosis Factors Of Differentiated Thyroid Carcinoma With Extrathyroidal Extension

BackgroundThyroid carcinoma is the most frequently endocrine system solid malignancy.In recent years,the incidence rate of thyroid carcinoma has been rising rapidly worldwide.Differentiated thyroid cancer(differentiated thyroid carcinoma,DTC)benign biological behavior,including thyroid papillary carcinoma(papillary thyroid carcinoma,PTC)and thyroid follicular carcinoma(follicular thyroid carcinoma,FTC).As the most type of thyroid cancer,the treatment of PTC mainly relies on surgery,and the overall effect is good.However,there are still some clinical features that affect its prognosis,such as the extrathyroidal extension(ETE)has been a hot topic of concern to clinicians.Patients with ETE are more aggressive,have higher rates of lymph node metastases,and are at greater risk of postoperative recurrence.Long-term follow-up and monitoring are important for patients with ETE.This study analyzed the clinicopathological features of extrathyroidal extension of differentiated thyroid carcinoma,analyzed the possible risk factors of ETE,and explored its influence on prognosis,so as to guide clinical treatment.ObjectiveTo analyze the unique biological characteristics of DTC patients with ETE and the differences in clinicopathological characteristics of DTC patients with or without ETE,explore the possible risk factors of DTC with ETE and their specific impact on prognosis.MethodsThe clinic-pathologic data of 592 newly diagnosed DTC patients admitted to our hospital from June 1,2015 to June 1,2016 were collected.The inclusion criteria:(1)age>18 years old;(2)Patients who underwent thyroid surgery for the first time in our hospital and were confirmed to be DTC by postoperative pathological routine results;(3)Complete clinic-pathologic data and follow-up information.The differences in clinicopathological characteristics between patients with DTC with or without ete were analyzed by chi square test and multiple logistic regression,and statistical methods such as univariate Kaplan Meier method and multivariate Cox proportional hazards model were used to analyze the association between clinicopathological indicators such as ete and prognosis,to explore the associated factors affecting disease-free survival(DFS).ResultsThere were 581 PTC cases and 11 FTC cases in 592 DTC patients,and 100 cases were accompanied with ETE(16.9%).Univariate analysis showed that the risk factors of DTC with ETE were tumor maximum diameter,multiple lesions of thyroid and lymph node metastasis in central or lateral cervical region(P<0.05).Multivariate analysis indicated that when the tumor maximum diameter was greater than and equal to 2cm(OR=2.371,95%CI 1.423～3.951,P<0.001),multiple lesions of thyroid(OR=2.622,95%CI1.625-4.230P<0.001),cervical lymph node metastasis(OR=1.914,95%CI 1.107～3.310,P=0.020)is an independent risk factor for DTC with ETE.The last follow-up time was December 31,2020,and the follow-up time range was 29-64 months,the median follow-up time was 60 months.During this period,18 cases were lost to follow-up,with a loss follow-up rate of 3.04%.The 3 year and 5 year disease-free-survival rates were 86.9%and 83.2%in patients with DTC combined with ETE,which were significantly lower than those in patients without ETE(P<0.001).Fruit single factor analysis displayed that the tumor maximum diameter,multiple lesions,transfer,their neck lymph node metastasis,lymph node in central region with ETE(P<0.001)are the influence factors of patients with postoperative recurrence,COX multi-factor regression results showed that the tumor’s largest diameter(HR:25.586,95%CI10.523～62.207,P<0.001),multiple lesions(HR:4.328,95%CI2.203～8.501,P=0.036),their neck lymph node metastasis(HR:2.337,95%CI1.145-4.770,P=0.021)and ETE(HR:10.56,95%CI3.712-30.063,P<0.001)were independent influencing factors for postoperative recurrence of DTC patients.Conclusion1.Large tumor diameter(≥2cm),multiple lesions and enlarged cervical lymph nodes are the risk factors for DTC associated with ETE.2.In DTC patients with ETE,the incidence of central lymph node and cervical lymph node metastasis is higher,and relevant lymph node dissection should be carefully performed intraoperatively.3.The 5-year disease-free survival time of patients with ETE is lower,which is an independent factor affecting recurrence,and long-term follow-up should be emphasized after surgery.