Prediction Mode of More Than 5 Central Lymph Nodes Metastases in Clinically Node-negative Ipsilateral Papillary Thyroid Carcinoma with Tumor Size 1 to 4 cm

According to the 2015 American Thyroid Association guidelines, either lobectomy or total thyroidectomy was recommended for patients with papillary thyroid carcinoma (PTC) of 1 to 4 cm without extrathyroidal extension and lymph node metastasis. However, lymph node metastases showed strong association with recurrence and low survival rate, especially in PTC patients with more than 5 metastatic lymph nodes. Therefore, this study aimed to investigate the predictive factors of more than 5 central lymph nodes metastases (CLNM) in PTC patients with tumor sizes of 1 to 4 cm. A total of 382 patients with clinically node-negative (cN0) ipsilateral PTC who underwent thyroidectomy with central neck dissection between January 2012 and December 2016 were retrospectively analyzed. CLNMs of >5 were found in 54 (14.1%) patients, while CLNM was detected in 230 (60.2%) patients. Multivariate logistic regression revealed age < 45 years (P < .001), male gender (P = .013), and tumor sizes of >2 cm (P = .001) as independent predictive factors of >5 CLNMs in cN0 ipsilateral PTC patients with tumor sizes 1 to 4 cm. The prediction equation (Y = 1.694 × age + 0.807 × gender + 1.190 × tumor size - 3.530) was developed, with a sensitivity (57.4%) and a specificity (80.8%), respectively, at an optimal cut-off point of -1.685. Therefore, if the predictive value was higher than -1.685 according to the equation in cN0 ipsilateral PTC patients with tumor sizes 1 to 4 cm, then total thyroidectomy might be considered.