[Risk factors and preoperative evaluation of lymph nodes posterior to right recurrent laryngeal nerve metastasis in thyroid papillary carcinoma].

Objective: To investigate the risk factors and preoperative evaluation of lymph nodes posterior to right recurrent laryngeal nerve (LN-prRLN) metastasis in papillary thyroid carcinoma (PTC). Methods: Clinical data of 301 patients with right or double lobes who underwent surgery between August 2015 and October 2016 in the Department of Thyroid Surgery, the First Hospital of China Medical University, were retrospectively analyzed. The relationships between LN-prRLN metastasis and clinical pathology data and other factors were analyzed. The enhanced CT difference of LN-prRLN was analyzed by receiver operating characteristic (ROC) curves. Results: LN-prRLN metastasis was detected in 46 patients. Univariate analysis showed that age, tumor diameter, Delphian lymph node metastasis, lymph nodes anterior to right recurrent laryngeal nerve (LN-arRLN) metastasis number, and the number of lateral compartment lymph node metastases were significantly associated with LN-prRLN metastasis (all P<0.05). Multivariate logistic regression analysis showed that LN-arRLN metastasis and right lateral compartment lymph node metastasis were independent risk factors for LN-prRLN metastasis (both P<0.05). The area under the ROC curve for contrast-enhanced thyroid CT was 0.948 (P<0.001), the cut-off value was 72 Hu, and the best sensitivity and specificity were 90.5% and 94.1%, respectively, with a Youden index of 0.846. Conclusion: LN-prRLN dissection is recommended when there exists LN-arRLN metastasis or right lateral compartment lymph node metastasis in patients with PTC, especially when preoperative contrast-enhanced CT shows LN-prRLN and contrast-enhanced CT is ≥72 Hu.