First-Line Systemic Treatment of RAI-Refractory Advanced or Metastatic Follicular Thyroid Cancer
When follicular thyroid cancer no longer concentrates radioactive iodine and has progressed to advanced or metastatic disease, systemic therapy becomes necessary. This protocol defines the first-line approach for this clinical situation.
Clinical Scenario
The patient has follicular thyroid cancer that is refractory to radioactive iodine (RAI) treatment, with advanced local or distant metastatic spread. RAI refractoriness means further iodine-based treatment is not a viable option and systemic intervention is required.
Treatment Goals
The primary objective is halting disease progression — defined as the absence of a 20% or greater increase in target lesion size and no appearance of new lesions, assessed by RECIST v1.1 on cross-sectional imaging. Reductions in serum thyroglobulin are expected in patients who respond to treatment.
References
- Lenvatinib and sorafenib should be considered the standard first-line systemic therapy for RAI-refractory DTC [I, A; ESMO-Magnitude of Clinical Benefit Scale (ESMO-MCBS) v1.1 scores: 3 for lenvatinib, 2 for sorafenib].
- In the DECISION trial, 417 patients were randomised (1 : 1) to treatment with sorafenib or placebo, with crossover permitted at disease progression.
- The results of chemotherapy administration (e.g. doxorubicin) in RAI-refractory DTC are disappointing; therefore, it is not recommended unless MKI therapy is contraindicated.
- Reductions in serum Tg are expected in responders, but clinical decisions cannot be based on this parameter alone.
- The imaging assessment should be repeated every 3–12 weeks during treatment.