Predictive value of baseline thyroid autoantibody titers for ICI-associated thyroid adverse events in cancer

Objective: To investigate the predictive value of pretreatment thyroid autoantibody titers for thyroid immune-related adverse events (irAEs) in patients receiving immune checkpoint inhibitors (ICIs). Methods: In this study, 181 patients with malignancies treated with ICIs between January 2022 and October 2025 were retrospectively analyzed. The patients were categorized based on the occurrence of thyroid irAEs. Risk factors and the impact of antibody titers were analyzed using logistic regression and Kaplan-Meier methods. Results: Thyroid irAEs occurred in 44 (24.3%) patients, predominantly including hypothyroidism (81.8%). Logistic regression revealed that baseline thyroid-stimulating hormone (TSH) levels, thyroid peroxidase antibody (TPOAb) positivity, and thyroglobulin antibody (TgAb) positivity were significant risk factors (P < 0.05). Kaplan-Meier analysis revealed a significantly higher incidence of irAEs in patients with elevated baseline TPOAb and TgAb titers than in those with normal titers (P < 0.01). Notably, severely elevated TPOAb titers resulted in a significantly higher risk of irAEs than moderately elevated titers (P < 0.05), whereas the corresponding difference for TgAb titers was not significant. Conclusion: Baseline TPOAb and TgAb titers are effective predictors of thyroid irAEs. Higher TPOAb titers are correlated with an increased risk, thereby supporting the utility of quantitative baseline screening for risk stratification.