The prognostic factors for clinical N1b patients in thyroid papillary carcinoma

ABSTRACT

Background: The aim of this study is to determine the prognostic factors which affect both disease-free survival (DFS) and overall survival (OS) in thyroid papillary carcinoma with clinical lateral lymph node metastasis. Methods: One hundred and three papillary thyroid carcinomas diagnosed in adult patients received therapeutic lateral neck dissection between December 1989 and June 2010 were analyzed retrospectively. All of the patients were classified as American Thyroid Association (ATA) intermediate risk category. Age, gender, tumor stage and size, multicentricity and bilaterality, vascular invasion and extrathyroidal invasion, ipsilateral/contralateral lymph node involvement, lymph node ratio, extranodal tumor extension, and development of recurrence were the factors which might affect disease-free and OS. Univariate and multivariate analyses were performed. ROC analysis was used to find the cutoff value for lymph node ratio. Results: One hundred and three patients were followed median 101 months. Locoregional or systemic recurrence developed in 20 patients (19.4%) while 7 patients (6.8%) had persistent disease. In multivariate analysis, lymph node ratio (P = 0.003, relative risk [RR] 5.4, 95% confident interval [CI] 1.7–16.5) and contralateral lymph node involvement (P = 0.02, RR 4.9, 95% CI 1.3–18.5) were the independent factors affecting DFS where contralateral lymph node involvement (P = 0.009, RR 44.4, 95% CI 2.5–765.2) was the only factor which affected OS. Conclusions: Lymph node ratio and contralateral metastasis affect DFS while contralateral metastases only affect OS in patients with N1b thyroid papillary carcinoma