The Significance Of Central Lymph Node Dissection In Managemant For Papillary Thyroid Microcarcinoma

Objective:The role of central lymph node dissection (CLND) for papillary thyroid microcarcinoma (PTMC) has been debated. According to the risk factors for central lymph node metastasis (CLNM) in PTMC in this paper, significance of PTMC for CLND were explored.Methods:968 cases of thyroid carcinoma and 250 cases of thyroid carcinoma were collected in January 2011 to December 2014 in our department. While Clinical data and results of neck lymph node metastasis of 94 patients with PTMC, who had underwent the first surgical treatment by the same surgery operator.Results:One case was follicular carcinoma and the rest was PTMC in these 250 cases of thyroid carcinoma.94 cases who were operated by the same surgeon were performed routine central lymph node dissection,82 patients underwent ipsilateral CLND, while 12 patients received bilateral CLND. Concurrent lateral neck lymph node dissection was performed in 32 patients (mainly III, IV areas). The incidence of central and lateral neck lymph node metastasis was 47.9% and 13.8%, respectively. Univariate analysis showed that CLNM was correlated with tumor size more than 5mm, multifocality, and primary tumor in the lower one third (P< 0.05), but not related to gender and age(P> 0.05).In the current criteria of cNO, 82 cases conformed to cN0 in 94 cases and the rest accorded with cNl. Postoperative disease seizure confirmed that the accuracy was 60.6%. With the standard for intraoperative frozen central lymph node evaluation of cervical lymph node metastasis, the accuracy was 87.2%. In these 13 cases who displayed lateral neck lymph node dissection, the metastasis rate of cervical lateral area is 20.0% when the number of CLNM was less than or equal to 1 piece. The metastasis rate of cervical lateral area was 58.8% when the number of CLNM was more than 2 pieces.Conclusion:The rate of PTMC in the CLNM is high. It is necessary to clean out the central lymph node. If the tumor mass is multifocality, greater than 5mm in diameter and located in gland under the lower one third, the risk of central metastasis increases. Intraoperative frozen of central lymph node had contributed to determination of the extent of lymph node metastasis to facilitate the operation to determine the scope of the thyroid and lymph nodesl.The accuracy of cervical lymph node metastasis by the cN0 current criteria was low.The intraoperative frozen central lymph node can assess objectively cervical lymph node metastasis.