Prediction of central compartment lymph node metastasis in papillary thyroid microcarcinoma.

OBJECTIVES

We aimed to determine the predictive factors for central compartment lymph node metastasis (LNM) in papillary thyroid microcarcinoma (PTMC).

DESIGN AND PATIENTS: We undertook a retrospective study of 291 patients treated for PTMC. The following criteria were assessed to predict the presence of central compartment LNM: sex, age, tumour multifocality, tumour size, tumour bilaterality, extracapsular spread (ECS), lateral neck LNM, coexistence of chronic lymphocytic thyroiditis, BRAF(V) (600E) mutation and ultrasonography (US) features. Univariate and multivariate analyses were performed to identify clinicopathological characteristics and US findings in predicting central compartment LNM from PTMC.

RESULTS

The central compartment LNM affected 133 (45.7%) of 291 patients. With use of univariate and multivariate analyses, male gender (OR 2.020; P = 0.039), tumour size (>5 mm) (OR 3.687; P = 0.015), ESC (OR 2.330; P = 0.044), lateral LNM (OR 15.075; P = 0.000) and BRAF(V) (600E) mutation (OR 2.464; P = 0.000) were independently correlated with central compartment LNM. Age, tumour multifocality, tumour bilaterality, coexistence of chronic lymphocytic thyroiditis and US characteristics were not significantly related to the presence of central compartment LNM. We have also developed a nomogram to predict the probability of central compartment LNM for an individual patient. The sensitivity was 71.9% and specificity was 70.3%, with an under the receiver operating characteristic (ROC) curve of 0.772.

CONCLUSIONS

A prophylactic neck dissection of the central compartment should be considered particularly in PTMC patients with male gender, a >5 mm tumour size, ECS of the tumours, lateral LNM and positive BRAF(V) (600E) mutation.