Preoperative High Level of Circulating Tumor Cells is an Independent Risk Factor for Central Lymph Node Metastasis in Papillary Thyroid Carcinoma with Maximum Lesion Diameter ≤1.0 cm.

Objective: Circulating tumor cell (CTC) has been used to assist in the diagnosis and progression assessment of solid tumors, but the relationship between preoperative CTCs levels and central lymph node metastasis (CLNM) of papillary thyroid carcinoma (PTC) needs to be clarified.

Methods: Data on clinical features (age, gender, Hashimoto's thyroiditis, multifocal, maximum lesion diameter, invaded capsule, clinical stage, and status of lymph node metastasis) of PTC patients treated at our hospital between June 2021 and April 2023 were retrospectively collected. The relationship between the CTCs level and these clinical features was analyzed, especially the relationship between the CTCs level and CLNM.

Results: A total of 705 PTC patients were included, and there were 333 (47.2%) patients with CLNM. Patients with a high CTCs level had higher proportions of multifocality, maximum lesion diameter >1cm, and CLNM than those in patients with a low CTCs level. Tumor size was connected to CTCs level, patients with a high CTCs level had a higher proportion of CLNM than those with a low CTCs level in PTC with maximum lesion diameter ≤1cm (45.3% vs 29.7%) (=0.001). Logistic regression analysis showed that age <55 years old (odds ratio (OR): 2.612, 95% confidence interval (CI): 1.565-4.361, <0.001), invaded capsule (OR: 1.662, 95% CI: 1.098-2.517, =0.016), and high CTCs level (≥8.7 FU/3mL, OR: 2.141, 95% CI: 1.431-3.203, <0.001) were associated with CLNM in PTC with maximum lesion diameter ≤1cm.

Conclusion: In PTC patients with maximum lesion diameter ≤1cm, patients with high preoperative CTCs level (≥ 8.7FU/3mL), age <55 years old, and capsular invasion were prone to CLNM. However, similar results were not observed in patients with maximum lesion diameter >1cm.