Update on the Systemic Management of Radioactive Iodine Refractory Differentiated Thyroid Cancer (Review)

The incidence of differentiated thyroid cancer (DTC) has increased over the last few decades, though it remains to be a rare disease. The prognosis of DTC is excellent; its treatment includes surgery (near-/total thyroidectomy), which is usually followed by remnant thyroid bed ablation using radio-iodine, as well as a risk-stratified follow-ups, including hormone replacement. Treatment of patients who are non-responsive to radioactive iodine (RAI) remains a challenge. Targeted therapies for RAI refractory DTC act primarily through inhibition of cell proliferation, survival and angiogenesis. Tyrosine kinase inhibitors (TKI) have achieved prolonged responses and improved progression-free survival, thereby representing a shift in the treatment of advanced thyroid cancer. There will be number of targeted treatment options for this patient population in the near future. Evidence regarding which drug should be used first and whether there is crossover drug resistance between these drugs is still lacking. Clinicians should be able to choose precisely which patients should be treated with novel targeted therapies after taking into account the following facts: i) TKIs have still not demonstrated a survival benefit. ii) The adverse effects of long-lasting treatment with TKIs could worsen quality of life, which is mostly excellent in these patients before starting treatment with these agents.