Prediction of radioactive Iodine-131 therapy efficacy based on postoperative clinical indicators in patients with differentiated thyroid cancer

Patients with differentiated thyroid cancer(DTC)typically receive postoperative radioactive iodine(RAI)therapy. Predicting RAI efficacy can facilitate early intervention and guide individualized treatment strategies. This retrospective study included101DTC patients who underwent surgery followed by RAI therapy. Patients were categorized into effective and ineffective response groups based on treatment outcomes. Univariate analyses were first performed to identify differences in demographic and postoperative clinical indicators between the two groups. The significant variables were first analyzed using XGBoost and multivariable logistic regression models. These analyses aimed to identify key factors affecting treatment efficacy. Based on these key factors, a nomogram was constructed in the training and validation sets, with model performance evaluated using calibration curves, ROC curves, and decision curve analysis(DCA). Finally, interactions among the key factors were examined. The ineffective group showed poorer demographic characteristics and postoperative clinical indicators(such as age, intraoperative blood loss, and surgery duration)compared to the effective group. Tumor size, postoperative Thyroxine (T4) level, postoperative Thyroglobulin (Tg) level, age, and length of hospital stay were identified as important predictors. It should be noted that the OR value of T4 is close to 1,indicating that its independent predictive value is relatively limited. The nomogram built on these five factors demonstrated good predictive performance. Significant interactions were found between tumor size and T4,and between length of hospital stay and Tg. This study developed a nomogram based on tumor size, postoperative T4,postoperative Tg, age, and length of hospital stay to predict RAI treatment efficacy in postoperative DTC patients. It also revealed significant interactions between tumor size and T4,as well as between hospital stay and Tg. This study may provide a reference for evaluating RAI efficacy in postoperative DTC patients.