| Background and Objective:Thyroid carcinoma(TC)is the most common endocrine malignant tumor,accounting for 5.0%of head and neck malignant tumors.Studies have shown that about 95%of TCs originate from thyroid follicular epithelial cells,including differentiated thyroid cancer,undifferentiated thyroid cancer,and a small amount of medullary thyroid carcinoma(MTC)that originates from parathyroid follicular cells.Among them,differentiated thyroid cancer includes papillary thyroid carcinoma(PTC)and follicular thyroid carcinoma(FTC).PTC accounts for 70%-80%of all TCs.Epidemiological studies have shown that the incidence of PTC has increased at a rate of nearly 4%per year in recent years.The vast majority of them are Papillary thyroid microcarcinoma(PTMC).PTC grows slowly and has a good prognosis,but early cervical lymph node metastasis is prone to occur,with a metastasis rate of 30%-90%.Lymph node metastasis is the main reason for the patient’s secondary surgery,which undoubtedly increases the difficulty of surgery and the incidence of postoperative complications.Therefore,taking a positive and effective method for cervical lymph node dissection is a very important part of thyroid surgical treatment.In the first edition of the NCCN guidelines for 2019,it is pointed out that if cervical lymph nodes in PTC patients are clinically visible or biopsy confirmed as metastatic lymph nodes,therapeutic dissection is required,but prophylactic dissection is not recommended for PTC patients with negative clinical lymph node evaluation(cN0).At present,the evaluation method of cN0 mainly relies on preoperative high-resolution color Doppler ultrasound,but it cannot accurately evaluate cN0.Some studies have shown that if color Doppler ultrasound is used as a means of evaluating cN0,the false positive rate and false negative rate are 1.9%and 2.9%.Prophylactic neck dissection in patients with stage CN0 PTC can be divided into prophylactic lymph node dissection and prophylactic cervical node dissection according to the scope of dissection.At present,most domestic guidelines and consensuses recognize the preventive dissection of lymph nodes in the central area,but no detailed recommendations have been given for preventive dissection of cervical lymph nodes.In recent years,many research teams have conducted preventive cervical lymph node dissection.Most of them have focused on the study of lymph node metastasis in lateral neck Ⅲ and Ⅳ areas.Previous data also show that the rate of lymph node metastasis in lateral neck areas Ⅲ and Ⅳ is the highest.There are few studies on the rules of lymph node metastasis and dissection in area Ⅱ.The purpose of this study was to analyze the risk factors of lymph node metastasis in patients with stage CN0 PTC in order to look for indications for dissection of lymph nodes in region Ⅱ.Methods:A retrospective analysis of 100 patients with cN0 PTC who had complete data from January 2016 to December 2018 in the Department of Thyroid Surgery of the Hospital.Each patient underwent lymph node dissection in the affected area Ⅱ-Ⅵ.Univariate analysis of risk factors and metastasis of lymph node metastasis in Zone Ⅱwas performed by 2 tests.Logistic regression was used to analyze the statistically significant indicators in the univariate analysis to determine the degree of influence of each variable.Further,the number of lymph node metastasis in the Ⅲ and Ⅳ regions of the contralateral neck and the lymph node metastasis in the second region were analyzed by 2 tests.Results:This group of 100 cases of patients with cN0 PTC cleaning the lymph node number 3546,metastasis lymph node number 768,the transfer rate was 21.66%,the central lymph node metastasis rate was 48.08%(301/626),Ⅲ district of lymph node metastasis rate was 26.11%(242/927),Ⅳ zone of lymph node metastasis rate was 18.01%(116/644),Ⅱ lymph node metastasis rate was 12.33%(92/746),V zone of lymph node metastasis rate was only 2.82%(17/603).The tumor was located in the upper pole(2=4.702,P=0.03),external invasion(2=22.161,P<0.001),region Ⅲlymph node metastasis(2=28.128,P<0.001),region Ⅲ and Ⅳ lymph node metastasis(2=35.620,P<0.001).When 2(2=4.675,P=0.031)region Ⅲ lymph node metastases,4(2=4.388,P=0.036)region IV lymph node metastases,and 3(2=4.177,P=0.041)region Ⅲ and Ⅳ lymph node metastases simultaneously,the lymph node metastases in region Ⅱ were statistically significant.Moreover,multivariate Logistic regression results showed that the risk of lymph node metastasis in region Ⅱ was 4.281(95%ci 1.129-16.227,P=0.032);patients with positive region Ⅲ and Ⅳ lymph nodes had an 8.322 risk of region Ⅱ lymph node metastasis(95%CI 1.782-38.873,P=0.007);patients with positive region Ⅲ lymph nodes had a risk of region Ⅱ lymph node metastasis of 6.804(95%CI 1.358-34.084,P=0.02);and the risk of region Ⅱ lymph node metastasis was 8.557(95%CI 1.904-38.458,P=0.005)in patients with tumors in the upper pole.Conclusion:When cN0 PTC patients have primary lesion invasion,located in the upper pole,ipsilateral Ⅲ lymph node metastasis≥2,ipsilateral Ⅳ lymph node metastasis≥4,ipsilateral Ⅲ and Ⅳ lymph nodes simultaneously≥3,should Actively expand the lymph nodes in the Ⅱ area. |
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