The Discussion On The Surgical Treatments Of Differential Thyroid Microcarcinoma

Objective:The study is designed to discuss the necessity of central lymph node dissection,prophylactic lateral neck lymph node dissection and the selection of surgical resection area for patients with differentiated thyroid microcarcinoma who were well diagnosed and need surgical treatments.Methods:1.A total of 255 patients with DTMC were enrolled as the study objects from January 2012 to October 2015 in the thyroid surgery department of Yongzhou Central Hospital of Hunan province.All 255 patients received surgical treatments and underwent lateral central lymph node dissection.According to the characteristics of primary lesions,group A included 172 patients with thyroidectomy in the affected side and isthmus,while group B consisted of 83 patients with near or total thyroidectomy.Total survival rate,disease-free survival rate and local recurrence rate were compared between the two groups.The univariate analysis and multivariate logistic regression analysis were performed to determine the factors that affected local recurrence.Data from group B were also determined for the potential difference in local recurrence between near-total thyroidectomy and total thyroidectomy.At the same time,the data of lymph node metastasis in central region of all enrolled patients were analyzed.2.The patients who underwent near or total thyroidectomy in group B were subdivided into group B1(31 cases with lateral central lymph node dissection and prophylactic lateral cervical lymph node dissection) and group B2(38 cases with lateral central lymph node dissection).The total survival rate,disease-free survival rate,local recurrence rate,and local recurrence curve were compared between the two groups.And the operation time,intraoperative blood loss,postoperative drainage volume and complications between the two groups were analyzed.3.All the statistical data and local recurrence curve were analyzed by SPSS 19.0 or stata 12.0 software.Measurement data were analyzed by t test,and enumeration data were assessed by ?~2 test.P<0.05 was recognized as clinical significance.Results:1.The total survival rate of group A and B was 100%.The disease-free survival rate was 98.84% and 92.77%respectively.Local recurrence rates were 1.16% and 7.23% respectively.The univariate analysis of the local recurrence of all enrolled patients showed no significant difference in age,gender,tumor size,or pathologic types(P>0.05).However,there was statistically difference in the primary lesions and the central lymph node metastasis(P<0.05).Further,logistic regression analysis showed that in group B,multiple lesions and capsule invasion were the main risk factors for local recurrence[Exp(B)=0.025,Sig=0.009].In group B,the difference between near total thyroidectomy and total thyroidectomy was statistically significant(P<0.05).2.The central region lymph node metastasis rate of 255 patients was 41.96%(107/255),among which the occult metastasis rate was 18.69%(20/107).3.Comparing group B1 with group B2,no distant metastasis were detected and all survived healthily in both groups during the follow-up.Local recurrence occurred in 2 and 3 patients respectively.The univariate analysis and local recurrence curve both indicated that there was no survival benefits in group B1,and local recurrence rate was similar to group B2 without significant difference(P>0.05).However,the former had more complications than the latter,and the difference was statistically significant(P<0.05).Conclusions:1.Those patients with well-defined thyroid microcarcinoma should undergo active surgical treatment and their specific surgical resection area should be selected according to the characteristics of the primary lesions:patients with unilateral single lesions should be treated with the thyroidectomy in the affected side combined with isthmus;for those with a high risk of recurrence,such as multiple lesions,capsule encroachment,should be given total thyroidectomy,which may reduce the local recurrence rate.2.The central area of the affected side of DTMC should be dissected,and preventive cervical lymph node dissection is not necessary.