Occult Central Lymph Node Metastasis in cN0 Papillary Thyroid Carcinoma Patients Undergoing TOETVA Procedure

In this study, we evaluate the rate of CLNM and related factors in patients with cN0 PTC undergoing transoral endoscopic thyroidectomy vestibular approach (TOETVA), a feasible and safe procedure that is widely approved for early stage PTC patients.

A cross-sectional study was performed on 346 patients who underwent TOETVA due to thyroid cancer in the Department of Oncology and Palliative Care, Hanoi Medical University Hospital, from January 2020 to December 2021. The clinical, surgical, and pathological characteristics were recorded.

The mean age was 36.1 ± 9.1 (13-67) years. Females accounted for 96%. Total thyroidectomy was applied in 55 cases (15.9%), and conservative thyroidectomy accounted for 291 (84.4%). The median number of harvested lymph nodes in ipsilateral and bilateral CND groups is 5 (IQR: 3-7) and 7 (IQR: 3-10). The median number of metastasized lymph nodes in these two groups is 2 (IQR: 1-3) and 3 (IQR: 2-6), respectively. The rate of CLNM was 39.9%. Thyroiditis increased the number of harvested lymph nodes: 8.3 ± 0.7 (1-24) nodes, p = 0.002. Tumor size on ultrasound, young age (<29 years old), and stage of tumor increased the possibility of CLNM, p < 0.05. Univariate and multivariate logistic regression revealed that young age (<29 years old) and gross tumor invasion were independent risk factors of high number of CLNM with p < 0.05.

In summary, CLNM rate in patients with cN0 PTC accounted for 39.9%. With the facilities of pCND by TOETVA, a procedure that is widely approved for early PTC and has excellent cosmetics and oncological results, pCND should be considered in patients with risk factors like young age or large tumor. High volume of CLNM is associated with young age and gross tumor extension, and total thyroidectomy should be indicated in these patient groups.