Significance of selective neck dissection in patients with cN0 thyroid carcinoma

Objective To investigate the significance of selective neck dissection in patients with cN0 thyroid carcinoma who have a high-risk of lateral neck lymph node metastasis.Methods Sixty three patients with cN0 thyroid carcinoma who have a high-risk of lateral neck lymph node metastasis were prospectively studied at the Department of Head and Neck Surgery,Cancer Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College between August 2006 and June 2011.The patients with cN0 thyroid carcinoma easy to occur neck lymph node metastasis include:The maximum diameter of primary tumor is ≥ 2 cm; The primary tumor invaded the thyroid capsule; Lymph node metastasis in level Ⅵ is found; Lymph node enlargement in level Ⅲ or/and Ⅳ were detected preoperatively by ultrasonography,but not considered as metastasis.The surgical procedure is that the selective neck dissection in level Ⅲ and Ⅳ is performed depending on the collar incision of thyroid surgery.The lymph node chosen from the specimen has a frozen section.If lymph node metastasis is found in the frozen section,a functional neck dissection should be performed through prolonging the collar incision.Results All cases were pathologically confirmed as thyroid papillary carcinoma.The occult metastasis rate of lateral neck lymph nodes was 39.7％.According to the univariate analysis,the patients with thyroid capsule invasion and lymph node metastasis in level Ⅵ were more likely to have lateral neck lymph node metastasis,and the occult metastasis rate was 46.9％ and 54.3％,respectively (P =0.028,P =0.008),and there were statistically no significant difference in the primary tumor size and the preoperative neck lymph node status by ultrasonography with occult metastasis of lateral neck lymph nodes (P =0.803 and P =0.072).According to the multivariate analysis,there was a significant correlation only between the lymph node metastasis in level Ⅵ and occult metastasis of lateral neck lymph nodes (P =0.017),but there was no significant correlation with the thyroid capsule invasion,primary tumor size and neck lymph node status by preoperative ultrasonography in prediction of occult metastasis of lateral neck lymph nodes (all P ＞ 0.05).Conclusions Selective neck dissection is feasible for the patients with cN0 thyroid carcinoma who have a high-risk lateral neck lymph node metastasis and the lateral occult metastatic lymph node can be promptly found and removed.We suggest that the selective neck dissection for level Ⅲ and Ⅳ should be routinely performed in cN0 thyroid carcinoma patients with thyroid capsule invasion and lymph node metastasis in level Ⅵ. Key words: Thyroid neoplasms;  Selective neck node dissection;  Clinical N0