The therapeutic responses to I-131 ablation in patients of differentiated thyroid carcinoma complicated with nodular goiter

IntroductionWe applied the response to therapy reclassification system (RTRS) to evaluate the disease status after surgery and I-131 therapy in differentiated thyroid carcinoma (DTC) patients with nodular goiter (NG).Materials and methodsA total of 268 DTC complicated with NG patients who underwent the I-131 treatment and thyroidectomy between 2010 and 2018 were analyzed. The RTRS were classified into excellent (ER), indeterminate (IDR), biochemical incomplete (BIR) and structural incomplete response (SIR). Logistic regression analysis were performed to evaluate the relevant clinicopathologic and laboratory variables in the prediction of non-ER (IDR, BIR and SIR).ResultsIn the logistic analysis, gender (OR: 3.543, P = 0.01), lateral cervical lymph node metastases (N1b) (OR: 6.646, P = 0.005), pre-ablation stimulated thyroglobulin (Ps-Tg) (OR: 0.859, P = 0.000), and anti-Tg antibody (TgAb) (OR: 64.546, P = 0.000) were predictor of non-ER. The cut-off value of ps-Tg for predicting the ER was 19.98 ng/mL with a sensitivity of 92.6% and specificity of 83.2%. The non-ER rate of N1b group was significantly higher than the central cervical LNM (N1a) group.ConclusionFor patients with DTC complicated with NG, the cut-off value of ps-Tg for predicting the ER was 19.98 ng/mL. N1b patients showed inferior responses to I-131 therapy compared to N1a patients.