Predictive Factors of Skip Metastasis in Papillary Thyroid Cancer.

BACKGROUND Skip metastasis is defined as metastasis incident to the lateral compartment without involvement of the central compartment, and is generally unpredictable in papillary thyroid cancer (PTC). The present study aimed to investigate the frequency and predictor value of skip metastasis in PTC patients. MATERIAL AND METHODS A total of 355 patients diagnosed with thyroid cancer who had received a prior complete thyroidectomy with bilateral central neck and ipsilateral lateral neck lymph node dissection were enrolled in this study. The clinicopathological and ultrasound features were analyzed. A univariate and multivariate analysis were performed to identify the risk factors of skip metastasis. RESULTS The frequency of skip metastasis was 12.4% (44/355). The PTC patients with skip metastasis exhibited fewer lymph node metastasis, which was more commonly detected in tumor size ≤1 cm (OR 9.354; p=0.001; 95% confidence interval (CI) 1.865-26.735), tumors located in upper pole (OR 3.822; p<0.001; 95% CI 1.935-7.549), without a well-defined margin (OR 2.528; p=0.016; CI 1.191-5.367), and extrathyroidal extension (OR 2.406; p=0.013; CI 1.691-4.367). CONCLUSIONS Skip metastasis was common in PTC. The PTC patients with a tumor size ≤1.0 cm, located in the upper pole, without a well-defined margin and extrathyroidal extension should be carefully evaluated for skip metastasis.