Risk factors for cervical lymph node metastasis in papillary thyroid microcarcinoma: a study of 1,587 patients

Objective: The purposes of this study were to identify risk factors for cervical lymph node metastasis and to examine theassociation between BRAFV600E status and clinical features in papillary thyroid microcarcinoma (PTMC). Methods: A total of 1,587 patients with PTMC, treated in Tianjin Medical University Cancer Institute and Hospital from January2011 to March 2013, underwent retrospective analysis. We reviewed and analyzed factors including clinical results, pathologyrecords, ultrasound results, and BRAFV600E status. Results: Multivariate logistic regression analyses demonstrated that gender (male) [odds ratio (OR) = 1.845, P = 0.000], age ( 6 mm) (OR = 2.137, P = 0.000), bilateralism (OR = 2.011, P = 0.000) andextrathyroidal extension (OR = 1.555, P = 0.001) served as independent predictors of central lymph node metastasis (CLNM).Moreover, CLNM (OR = 29.354, P = 0.000) served as an independent predictor of lateral lymph node metastasis (LLNM). Amongpatients with a solitary primary tumor, those with tumor location in the lower third of the thyroid lobe or the isthmus were morelikely to experience CLNM (P < 0.05). Univariate analyses indicated that CLNM, LLNM, extrathyroidal extension, andmultifocality were not significantly associated with BRAFV600E mutation. Conclusions: The present study suggested that prophylactic neck dissection of the central compartment should be considered inpatients with PTMC, particularly in men with tumor size greater than 6 mm, age less than 45 years, extrathyroidal extension, andtumor bilaterality. Among patients with PTMC, BRAFV600E mutation is not significantly associated with prognostic factors. For abetter understanding of surgical management of PTMC and the risk factors, we recommend multicenter research and long-termfollow-up.