Central lymph node metastasis in cN0 papillary thyroid carcinoma.

Purpose: To evaluate the predictive factors of central lymph node (CLN) metastasis and the relationship between the number of metastatic CLN and risk factors for recurrence or metastasis in papillary thyroid carcinoma (PTC) patients.

Methods: Patients with PTC who had undergone subtotal or total thyroidectomy and ipsilateral CLN dissection were retrospectively reviewed. According to the number of metastatic CLN, patients were divided into 3 Groups: Group A: N=0; Group B: N=1-2; Group C: N ≥3.

Results: Occult ipsilateral CLN metastasis was present in 34.2% (78/228) of the patients. Univariate analysis revealed that ipsilateral CLN metastasis was significantly higher in younger patients (age <45 years), in those with maximal carcinoma diameter ≥1 cm and in those who presented with extrathyroid extension of carcinoma. Multivariate analysis showed tumor size and age were independent risk factors for ipsilateral CLN metastasis. Patient group distribution was as follows: Group A: N=150 (65.8%); Group B: N=50 (21.9%); Group C: N=28 (12.3%). Tumor size increased as the number of metastatic CLN increased, but age decreased when the number of metastatic CLN increased. Patients with CLN metastasis (Group B and C) had larger tumor size than those without metastasis. For patients with extrathyroid extension, patients in Group C had a significant odds ratio (0.215, p<0.05).

Conclusion: A maximal carcinoma diameter ≥1 cm and younger age are associated with a higher rate of ipsilateral CLN metastasis in unilateral PTC patients. Prophylactic ipsilateral CLN dissection may be effective in the management of these patients. The number of metastatic CLN is negatively associated with prognostic factors including age, tumor size and extrathyroid extension.