The Impact of Nodular Goiter on the Short‐Term Efficacy of Radioactive Iodine Therapy for Differentiated Thyroid Carcinoma: A Propensity Score Matching Study

OBJECTIVE: To evaluate whether concomitant nodular goiter (NG) affects the short-term efficacy of radioactive iodine (RAI) therapy in postoperative differentiated thyroid carcinoma (DTC) patients. METHODS: A total of 1017 DTC patients who received initial RAI therapy between May 2018 and May 2025 were retrospectively enroled and divided into NG (n = 239) and Non-NG (n = 778) groups. Short-term efficacy was defined according to the 2015 American Thyroid Association (ATA) criteria. Univariable and multivariable logistic regression and propensity score matching (PSM) were used to assess the association between NG and short-term efficacy. Sensitivity analyses were repeated in the thyroglobulin antibody (TgAb)-negative subgroup. RESULTS: Before PSM, multivariable analysis showed that NG was associated with lower odds of non-excellent response (NER) (OR = 0.60, 95% CI: 0.41-0.87, p = 0.008). After PSM, 221 matched pairs were obtained and NG was no longer significantly associated with NER (OR = 0.67, 95% CI: 0.42-1.06, p = 0.089), whereas N1b stage (OR = 4.78, 95% CI: 1.50-18.38, p = 0.013) and elevated pretreatment stimulated thyroglobulin (sTg) (OR = 1.10, 95% CI: 1.06-1.14, p < 0.001) were independently associated with NER. Sensitivity analyses in TgAb-negative patients yielded consistent findings. In the overall cohort, the AUC of sTg for predicting NER was 0.814 in the NG group and 0.738 in the Non-NG group (DeLong p = 0.027); this difference was not observed in the TgAb-negative subgroup (0.854 vs. 0.846, p = 0.801). CONCLUSION: After controlling for measured baseline confounding using PSM, concomitant NG was not an independent factor associated with short-term RAI therapy efficacy in patients with DTC. N1b stage and elevated pretreatment sTg were independently associated with poor short-term response.