Prognostic value of cervical lymph node metastasis ratio in Asian papillary thyroid carcinoma 5-year relapse-free survival: a meta-analysis

Cervical lymph node metastasis occurs frequently in papillary thyroid carcinoma. We aim to analyze the predictive value of cervical lymph node metastasis ratio (LNR) in papillary thyroid carcinoma 5-year relapse-free survival in Asian. Databases (Web of Science, PubMed, EMBASE, OVID, Elsevier Science Direct, and ProQuest) were searched to get the related articles. General data, cut-off ratio of LNR, five years of disease-free survival ratio and relapse-free survival ratio at different LNR cut-off values were obtained directly from included literatures and analyzed by diagnostic meta-analysis. Deeks' funnel plot asymmetry analysis was done to identify the publication bias. A total of 3880 Asian papillary thyroid carcinoma (PTC) patients from 7 articles were included. The sensitivity, specialty, and Diagnostic Odds Ratio combined values of LNR were 0.77 [0.67, 0.85], 0.76 [0.62, 0.87], and 10.85 [5.41, 21.77] respectively. The AUROC value of LNR was 0.83 [0.80, 0.86]. Compared with the fixed probability (20%) in preliminary experiments, the positive likelihood ratio (PLR) increased to 45%, and the negative likelihood ratio (NLR) reduced to 7%. No publication bias was found by Deeks' test. In conclusion, LNR can be used as a moderate predictor in PTC 5-years relapse-free survival for Asian.