A nomogram predicting dysphagia risk after adjuvant iodine-131 therapy in patients with papillary thyroid carcinoma

To identify clinical risk factors for dysphagia after iodine-131 ( 131 I) therapy in patients with papillary thyroid carcinoma (PTC) and develop a validated risk-prediction nomogram.

Adult PTC patients treated with 131 I at the Department of Nuclear Medicine, Affiliated Hospital of Xuzhou Medical University, between January 2022 and October 2024 were retrospectively reviewed. All patients underwent total or partial thyroidectomy, had satisfactory postoperative wound healing, and had histopathologically confirmed PTC. Baseline clinical data, laboratory parameters, and pretreatment salivary gland function assessed by dynamic pertechnetate single-photon emission computed tomography/computed tomography were collected. Swallowing function was evaluated before treatment and at 6-month follow-up using the MD Anderson Dysphagia Inventory; dysphagia was defined as a total score less than 50. Variables significant in univariate analysis were entered into backward stepwise multivariate logistic regression. Independent predictors were used to construct a nomogram, which was assessed by area under the curve (AUC), bootstrap calibration, and decision curve analysis.

Among 201 patients, 68 (33.8%) developed dysphagia. Higher cumulative 131 I dose, smoking history, and baseline salivary gland dysfunction were independent predictors of dysphagia. The nomogram incorporating these factors showed excellent discrimination, with an AUC of 0.913, good calibration with a bootstrap mean absolute error of 0.013, and favorable clinical net benefit.

Higher 131 I dose, smoking history, and pre-existing salivary gland dysfunction independently predict dysphagia after 131 I therapy in PTC patients. This nomogram may support individualized risk assessment and preventive counseling before treatment.