Risk Factors for Predicting Lymph Nodes Posterior to Right Recurrent Laryngeal Nerve (LN-prRLN) Metastasis in Thyroid Papillary Carcinoma: A Meta-Analysis

OBJECTIVE: To evaluate the risk factors for predicting lymph nodes (LN) posterior to right recurrent laryngeal nerve metastasis in thyroid papillary carcinoma. METHODS: PubMed, PMC, EMBASE, and the Cochrane Library were systematically searched for articles published spanning 30/06/2009-30/8/2018 using multiple search terms. Thirteen articles involving 10,014 patients were reviewed in our meta-analysis. Stata 15.1 software was used for the meta-analysis. RESULTS: The rate of LN posterior to right recurrent laryngeal nerve (LN-prRLN) metastasis was 8.65%. Univariate analysis showed that age (P = 0.001), gender (P < 0.001), tumour size (P < 0.001), lateral LN metastasis (P < 0.001), extrathyroidal invasion (P < 0.001), multifocality (P = 0.005), capsule invasion (P < 0.001), tumour location (P = 0.076), lymph nodes anterior to right recurrent laryngeal nerve (LN-arRLN) metastasis (P < 0.001), and central LN metastasis (P < 0.001) were significantly associated with the increased incidence of LN-prRLN metastasis in thyroid papillary carcinoma. CONCLUSION: PTC patients aged <45, male, and with tumours > 1 cm, lateral LN metastasis, extrathyroidal invasion, multifocality, capsule invasion, LN-arRLN metastasis, or central LN metastasis were significantly correlated with lymph nodes posterior to right recurrent laryngeal nerve metastasis, indicating LN-prRLN dissection.