Risk factors and nomogram for predicting central lymph node metastasis in papillary thyroid carcinoma based on gasless transaxillary endoscopic thyroidectomy

Background: Gasless transaxillary endoscopic thyroidectomy (GTET) offers superior cosmetic outcomes for patients with unilateral papillary thyroid carcinoma (PTC). Accurate preoperative prediction of central lymph node metastasis (CLNM) risk is crucial for determining the extent of central lymph node dissection in this minimally invasive approach. This study aims to develop and validate a nomogram for predicting CLNM in patients with PTC undergoing GTET.

Methods: A total of 377 PTC patients who underwent GTET in the past four years were included, comprising 260 patients without CLNM and 117 patients with CLNM. Independent risk factors were identified via least absolute shrinkage and selection operator (LASSO) regression and multivariate logistic regression analyses to construct a nomogram model. Internal validation was performed using bootstrap resampling. Model discrimination, calibration, and clinical utility were evaluated using receiver operating characteristic (ROC) curves, the concordance index (C-index), calibration curves, and decision curve analysis (DCA).

Results: Younger age, prolonged operative time, larger tumor diameter, a greater number of dissected lymph nodes, and higher preoperative free thyroxine (FT4) levels were identified as independent risk factors for CLNM. The model yielded a C-index of 0.797 [95% confidence interval (CI): 0.758–0.847], which remained robust at 0.787 (95% CI: 0.740–0.834) following bootstrap validation. The calibration curve demonstrated high concordance between predicted probabilities and actual incidences. Furthermore, the DCA curve indicated that the model offers a favorable clinical net benefit across a threshold probability range of 5% to 80%.

Conclusions: This study presents a predictive model for evaluating CLNM risk in PTC patients undergoing GTET. This tool facilitates the advancement and broader adoption of this surgical approach and provides an objective rationale for clinical decision-making regarding central lymph node dissection within this surgical context.