ABSTRACT
PURPOSE: Cervical lymph node metastasis in patients with papillary thyroid microcarcinoma (PTMC) is associated with an increased recurrence rate and distant metastases. In this study, we analyzed the predictive factors of lateral metastasis in patients with PTMC. METHODS: We retrospectively reviewed the medical records of 1,030 patients with PTMC who underwent thyroidectomy. The clinicopathological characteristics and radiological findings upon ultrasonography (US) and computed tomography (CT) were then analyzed to evaluate the predictability of lateral metastasis of PTMC. RESULTS: The overall rate of lateral metastasis was 3.3% for the 1,030 patients with PTMC. All patients underwent central lymph node dissection (CLND), and 119 of these patients (11.6%) underwent either prophylactic or therapeutic selective neck dissection (SND). Among patients who underwent lateral node evaluation, 28.6% had lateral metastasis. We found that lateral metastasis was associated with larger tumor size, extrathyroidal extension, multiple tumors, bilateral tumors, CLN metastasis, and positive expression of thyroid peroxidase. Positive findings of CLN and lateral metastases on ultrasonography (US) and computed tomography (CT) were significantly associated with lateral metastasis. CONCLUSION: This study demonstrated that, for patients with PTMC, larger tumor size, extrathyroidal extension, multiple tumors, bilateral tumors, CLN metastasis, positive expression of thyroid peroxidase, and positive CLN and lateral metastases identified on US and CT were significantly associated with lateral metastasis. Further studies with a large prospective study and longer follow-up are needed to clarify the predictive value of these factors.