Risk Factors for Local Recurrence in Patients With N1b Papillary Thyroid Carcinoma

Background and Objectives Papillary thyroid carcinoma (PTC) with lateral neck lymph node metastasis is known as a major risk factor for tumor recurrence after surgical treatment. The aim of this study is to identify risk factors for loco-regional recurrence in patients with PTC with lateral neck lymph node metastasis, which has a high risk of recurrence.Subjects and Method This study involved 319 patients who underwent total thyroidectomy, central lymph node (LN) and lateral LN dissection due to PTC. The patients’ demographics and pathological factors, including lymph node metastasis were retrospectively reviewed. Univariate, multivariate and C-index with variable selection analyses were performed to identify factors associated with recurrence-free survival (RFS).Results A mean follow-up of 101 months, 35 (10.9%) patients had a loco-regional recurrence. In multivariate analysis according to loco-regional recurrence, patients with a primary tumor of more than 4 cm, multifocality, vascular invasion, and bilateral lateral cervical metastasis were associated with worse RFS. In the variable selection analysis, lateral lymph node metastasis ratio was also statistically significant.Conclusion PTC with lateral neck lymph node metastasis included tumors larger than 4 cm. Multifocality, vascular invasion, high lateral lymph node metastasis ratio and bilateral neck lymph node metastasis are predictive factors of loco-regional recurrence, and these risk factors should be carefully followed-up after surgery.