Clinical value and indication for the dissection of lymph nodes posterior to the right recurrent laryngeal nerve in papillary thyroid carcinoma

Lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) are common sites of nodal recurrence after the resection of papillary thyroid carcinoma (PTC). However, the indication for LN-prRLN dissection remains debatable. We therefore studied the relationships between LN-prRLN metastasis and the clinicopathological characteristics in 306 patients with right or bilateral PTC who underwent LN-prRLN dissection. We found that LN-prRLN metastasis occurred in 16.67% of PTC and was associated with a number of the clinicopathological features. The receiver-operator characteristic (ROC) analysis showed that the areas under the ROC curves for the prediction of LN-prRLN metastasis by the risk factors age < 35.5 years, right tumor size > 0.85 cm, lymph node (right cervical central VI-1) number > 1.5, metastatic lymph node (right cervical central VI-1) size > 0.45 cm, and lymph node number in the right cervical lateral compartment > 0.5 were 0.601, 0.815, 0.813, 0.725, and 0.743, respectively. In conclusion, the risk factors for LN-prRLN metastasis in patients suffering right thyroid lobe or bilateral PTC include age <= 35.5 years, right tumor size >= 0.85 cm, capsular invasion, metastatic lymph node (right cervical central VI-1) number >= 2, metastatic lymph node (right cervical central VI-1) size >= 0.45 cm, and metastatic lymph node number in the right cervical lateral compartment >= 1. In patients whose risk factors can be identified pre-operatively or intraoperatively, the dissection of LNpr- RLN should be considered during right cervical central compartment dissection.