Predicting lymph node metastasis posterior to the right recurrent laryngeal nerve in papillary thyroid carcinoma: A risk model based on prelaryngeal and paratracheal lymph nodes

OBJECTIVE: To identify independent risk factors for lymph node metastasis posterior to the right recurrent laryngeal nerve (RLN) in cN0 papillary thyroid carcinoma and develop a predictive model for preoperative risk stratification. METHODS: A retrospective analysis was conducted on 721 cN0 papillary thyroid carcinoma patients that underwent lymph node dissection posterior to the right RLN between 2016 and 2019. Univariable and multivariable logistic regression analyses were used to assess clinical and pathological characteristics, and a nomogram was constructed. The model was validated using receiver operating characteristic curves and calibration curves. RESULTS: The incidence of lymph nodes posterior to the right was 19.8%. Multivariable analysis revealed three independent predictors: the number of paratracheal lymph node metastases (OR = 1.360, p = 0.021), combined prelaryngeal and paratracheal lymph node metastases (1-2 involved nodes: OR = 3.433; ⩾ 3 involved nodes: OR = 4.402, p < 0.05), and extrathyroidal extension (OR = 0.580, p = 0.021). CONCLUSION: This model provides a quantitative tool for intraoperative risk assessment and guides the development of individualized surgical plans for high-risk patients with cN0 papillary thyroid carcinoma.