A simplified preoperative model for predicting lymph node metastasis and post-ablation progression risk in papillary thyroid carcinoma

BACKGROUND: This study aimed to develop a simplified preoperative model for predicting lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC) and to evaluate its value in stratifying post-ablation progression risk. METHODS: A retrospective development cohort of 648 patients with T1 PTC and an independent validation cohort of 290 patients treated with microwave ablation were included. Least absolute shrinkage and selection operator regression and multivariable logistic regression were used to construct the model. Model performance was evaluated using receiver operating characteristic and calibration analyses. RESULTS: Foci number, tumor size, and punctate echogenic foci were identified as independent predictors of LNM and were included in the simplified model. The model achieved an area under the curve of 0.790 in the development cohort. In the validation cohort, increasing risk groups showed progressively higher rates of disease progression and newly developed LNM during follow-up. CONCLUSION: The simplified preoperative model showed good performance for predicting LNM and stratifying post-ablation progression risk in PTC, supporting its potential role in individualized surveillance and clinical management.