Risk factors of central compartment lymph node metastasis posterior to the right recurrent laryngeal nerve in differentiated thyroid carcinoma: A single-center prospective study in Vietnam

The study aims to examine the incidence of central compartment lymph node metastasis on the right side posterior to the recurrent laryngeal nerve in cases of papillary thyroid cancer, as well as the risk factors that may increase this incidence. A total thyroidectomy was conducted on 230 patients diagnosed with differentiated thyroid cancer, accompanied by right central compartment lymph node dissection at Viet Nam National hospital of endocrinology in 2024. The central lymph nodes were categorized into two groups: pre-nerve lymph nodes and post-nerve lymph nodes. The clinical and paraclinical characteristics of the primary tumor and metastatic cervical lymph nodes were documented. The result showed that 52 cases (22.6 %) presenting metastatic lymph nodes. Age >55 years, female gender, tumor size exceeding 1 cm, concurrent thyroiditis, and metastasis to pre-nerve central lymph nodes and ipsilateral lateral neck lymph nodes were significantly correlated with elevated rates of metastasis to lymph nodes located posterior to the recurrent laryngeal nerve (p < 0.05). Tumor location, multifocality, and extrathyroidal invasion did not significantly influence the metastasis rate to post-nerve lymph nodes (p > 0.05). Multivariate regression analysis revealed four independent prognostic factors for post-nerve lymph node metastasis: tumor size exceeding 1 cm, concurrent chronic thyroiditis, metastasis to pre-nerve lymph nodes, and metastasis to ipsilateral lateral neck lymph nodes. In conclusion, patient with above characteristics, precise dissection is recommended to prevent the oversight of metastatic lymph nodes. • The incidence of post-recurrent laryngeal nerve metastasis is 22.6% • Independent prognosis factors: Tumor ≥1 cm, chronic thyroiditis, pre-nerve, ipsilateral lateral neck lymph nodes metastasis