Patients With Differentiated Thyroid Cancer Who Underwent Radioiodine Thyroid Remnant Ablation With Low-Activity 131I After Either Recombinant Human TSH or Thyroid Hormone Therapy Withdrawal Showed the Same Outcome After a 10-Year Follow-up

Background: No long-term follow-up data are available for differentiated thyroid carcinoma (DTC) patients prepared with either exogenous or endogenous TSH and treated with low-activity (1.1 GBq [30 mCi]) radioiodine (I-131). Aim: The aim of this study was to evaluate the 10-year follow-up of DTC patients who underwent remnant ablation with 1.1 GBq I-131 after L-T-4 withdrawal, recombinant human TSH (rhTSH) administration, or both. Patients: A total of 159 DTC patients treated with total thyroidectomy and 1.1 GBq (30 mCi) of I-131 for remnant ablation and stimulated with rhTSH and/or endogenous TSH were separated into ablated (n = 115) and not ablated (n = 44) patients and prospectively followed-up for at least 10 years. In addition, we evaluated several features that could correlate with the final status of patients. Results: During the follow-up, 4 of 115 (3.5%) ablated patients showed a recurrence and 1 was successfully cured. Among not ablated patients, 16 of 44 (36.4%) had a persistent disease. At the end of the 10-year follow-up, 140 of 159 (88.1%) patients were disease-free, whereas 19 of 159 (11.9%) remained affected. No correlation was found with the type of TSH stimulation, and no other clinical and pathological features showed any correlation with the final status. However, low levels of stimulated serum thyroglobulin (<5.4 ng/mL) at first control after remnant ablation identified a subgroup of not ablated patients who became spontaneously cured. Conclusions: Long-term outcomes are similar in DTC patients treated with 1.1 GBq (30 mCi) I-131 and prepared either with rhTSH or endogenous TSH. It is of interest that serum thyroglobulin at first control after ablation can have a prognostic role.