Ipsilateral and contralateral central lymph node metastasis in papillary thyroid cancer: patterns and predictive factors of nodal metastasis.

BACKGROUND The aims of this study were to evaluate the rate and risk factors of ipsilateral and contralateral central lymph node (CLN) metastases in patients with papillary thyroid cancer (PTC). METHODS A total of 161 patients who underwent total thyroidectomy with prophylactic CLN dissection (CLND) to treat PTC were enrolled. RESULTS Of 134 total cases excluding tumors located in the isthmus and bilateral lobes, 72 cases (53.7%) involved CLN metastases. Tumor size, age, and sex were found to be predictive of ipsilateral CLN metastasis and the rate of ipsilateral CLN metastasis in tumors > 1 cm was 59.6%. Contralateral CLN metastases were more prevalent only in tumors that already had ipsilateral CLN metastases (27.3%, p = .002). CONCLUSIONS It is suggested that risk factors of ipsilateral and contralateral CLN metastases should be considered while planning the extent of CLND in patients with clinically node-negative and unilateral PTC upon preoperative ultrasonography.