Risk factors for neck nodal metastasis in papillary thyroid microcarcinoma: a study of 1066 patients.

CONTEXT: The surgical management of papillary thyroid microcarcinoma (PTMC), especially regarding the necessity of central lymph node dissection, remains controversial.

OBJECTIVE

The objective of the study was to describe the clinicopathological features of PTMC and to identify the risk factors for central lymph node metastasis (CLNM) that can guide surgical strategies for patients with PTMC.

DESIGN

In this retrospective cross-sectional study, risk factors and outcome variables were assessed at the time of surgery for the primary tumor.

SETTING

The study was conducted at a university-based tertiary care cancer hospital.

PATIENTS: Data from the medical records of 1066 consecutive patients diagnosed with PTMC over a 5-yr period were analyzed.

RESULTS

Our multivariate logistic regression analysis found male gender, younger age (≤45 yr of age), multifocal lesions, extrathyroidal extension, and larger size of the primary tumor (>6 mm) to be associated with CLNM; multifocal lesions were associated with the highest risk (odds ratio 4.476, 95% confidence interval 2.975-6.735). Extrathyroidal extension, multifocal lesions, and CLNM were associated with lateral neck lymph node metastasis (LLNM). In patients with a solitary primary tumor, tumor location in the upper third of the thyroid lobe was associated with a lower risk of CLNM and a higher risk of LLNM.

CONCLUSIONS

Prophylactic central lymph node dissection need be considered in PTMC patients presenting with risk factors. In PTMC patients with a solitary primary tumor, tumor location can assist in the evaluation of LLNM. We recommend multicenter research and long-term follow-up to better understand the risk factors and surgical management of PTMC.