The prognostic value of central excised lymph node count in N1a papillary thyroid cancer: a population-based study.

BACKGROUND: The optimal number of excised lymph nodes (ELNs) during central-compartment neck dissection for papillary thyroid cancer (PTC) remains unclear. This study aimed to investigate the association between central ELN count and overall survival (OS) in PTC patients with N1a disease. METHODS: Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015, encompassing a total of 10,445 patients with N1a PTC. Restricted cubic splines (RCSs) were used to characterize the relationship between ELN count and OS. Multivariate Cox proportional hazards models and sensitivity analyses were employed to assess the association. RESULTS: Among the 10,445 patients, the RCS revealed an L-shaped association between the number of ELNs and OS (P for non-linearity <0.05), with a threshold identified at 5 ELNs. Below this threshold, each additional ELN was associated with a 15% decrease in the risk of death [hazard ratio (HR), 0.85, 95% confidence interval (CI): 0.76-0.95]. However, no significant survival benefit was observed when ELN count exceeded 5 (HR, 1.00; 95% CI: 0.97-1.04). Sensitivity analyses confirmed similar correlations between the ELN count and OS. CONCLUSIONS: Our study revealed an L-shaped association between central ELNs and OS in N1a PTC patients, suggesting ELN count serves as a prognostic indicator and a threshold of 5 ELNs may optimize survival outcomes. Further validation is required to address potential biases, including unmeasured confounders inherent in retrospective data.