Level IIb lymph node metastasis characteristics and predictive factors for patients with cN1b papillary thyroid carcinoma.

Background: The aim of the present study was to examine the frequency, characteristics, and risk factors of level IIb lymph node metastases in papillary thyroid carcinoma. Methods: We reviewed and collected clinical and pathological records for 954 papillary thyroid carcinoma patients with clinically positive lateral neck node metastasis. Univariate and multivariate analyses were performed to detect risk factors for level IIb lymph node metastasis; a predictive model was built based on multivariate analysis and tested in a validation group. Results: Level IIb lymph node metastasis was observed in 137 of 954 patients (14.4%). Univariate and multivariate analyses using the training group indicated that gross extrathyroidal extension of the primary tumor, tumor location in the upper pole, and preoperative distant metastasis were 3 independent risk factors for level IIb lymph node metastasis. This model was built and tested in a validation group, and the area under the curve was 0.840 (P < .001). The cutoff of the IIb score was 12, which was tested in the validation group; the sensitivity was 82.1% and the specificity was 95.6%. Conclusion: Level IIb dissection should be performed in select patients with IIb scores >= 12. (C) 2020 Elsevier Inc. All rights reserved.