Is empirical radioactive iodine therapy still a valid approach to patients with thyroid cancer and elevated thyroglobulin?

Thyroid. 2014 Mar;24(3):533-6. doi: 10.1089/thy.2013.0427. Epub 2013 Dec 10.


Background: At present, empirical radioactive iodine therapy is recommended for patients with thyroid cancer and elevated thyroglobulin (Tg) after initial therapy when neck ultrasonography (US), chest computed tomography (CT), and 18-fluorodeoxyglucose positron emission tomography (FDG-PET) do not reveal metastases. The objective of this study was to determine whether empirical (131)I therapy is indeed useful in these patients.

Methods: Patients with papillary thyroid cancer submitted to total thyroidectomy followed by remnant ablation with (131)I in whom whole-body scanning at the time of ablation (WBS-ablation) did not reveal metastases and who had elevated Tg after initial therapy were selected. Included in the study were patients with basal Tg >2 ng/mL or Tg >5 ng/mL after stimulation with recombinant human thyrotropin or Tg >10 ng/mL after levothyroxine withdrawal for 4 weeks. All patients were first investigated by neck US and chest CT. FDG-PET/CT was performed in patients with negative US and CT. The final sample of this study consisted of patients with negative US, CT, and FDG-PET/CT. These patients received an activity of 100 mCi (131)I and were submitted to posttherapy WBS (RxWBS).

Results: Among the 24 patients receiving empirical (131)I therapy, no ectopic uptake was seen in 23 and mild uptake in the thyroid bed (<0.5%) in 15. Only one patient presented pulmonary metastases detected by RxWBS. Disease was observed in two other patients during short-term follow-up (mean 22 months), one with lymph node metastases diagnosed by a repeat US and one with bone metastases diagnosed by CT and FDG-PET scans.

Conclusions: We conclude that RxWBS rarely reveals disease in patients with elevated Tg after ablation, but with negative findings on WBS-ablation, US, CT, and FDG-PET. In this situation, empirical (131)I therapy should be restricted to patients with documented progression of serum Tg.

MeSH terms

  • Adult
  • Aged
  • Carcinoma, Papillary / blood
  • Carcinoma, Papillary / pathology
  • Carcinoma, Papillary / radiotherapy*
  • Carcinoma, Papillary / surgery
  • Female
  • Humans
  • Iodine Radioisotopes / therapeutic use*
  • Male
  • Middle Aged
  • Thyroglobulin / blood
  • Thyroid Neoplasms / blood
  • Thyroid Neoplasms / pathology
  • Thyroid Neoplasms / radiotherapy*
  • Thyroid Neoplasms / surgery
  • Thyroidectomy
  • Young Adult


  • Iodine Radioisotopes
  • Thyroglobulin