Risk factors for central neck lymph node metastasis of clinically noninvasive, node-negative papillary thyroid microcarcinoma.

Background: To examine predictive factors for subclinical central neck lymph node metastases (LNM) of papillary thyroid microcarcinoma (PTMC).

Methods: The clinical and pathological findings of 287 patients with clinically noninvasive, node-negative, solitary papillary thyroid carcinoma (PTC), who had undergone thyroidectomy plus central compartment neck dissection and showed pathologically confirmed nodal metastases, were analyzed. Predictive risk factors for central LNM were quantified.

Results: Pathologic LNM was identified in 63 (32.6%) PTMC patients and 48 (51.0%) PTC patients (tumor size >1 cm; P = .003). Tumor size (>.7 cm; P = .011), multifocality (P = .010), and microscopic extracapsular extension (P = .050) were significant variables predictive of central LNM from PTMC in univariate analysis. Tumor size (odds ratio 2.28, 95% confidence interval 1.19 to 4.38; P = .014) and multifocality (odds ratio 2.38, 95% confidence interval 1.14 to 4.93; P = .020) were independent variables predictive of central LNM in multivariate analysis.

Conclusions: Cervical LNM is highly prevalent in clinically noninvasive, node-negative PTC. Central neck LNM is associated with larger tumor size and multifocality of PTMC.