Update on the diagnosis and therapy of distant metastases of differentiated thyroid carcinoma.

Differentiated thyroid cancer, when adequately treated, has an overall good prognosis. However, 10-15% of patients develop distant metastases. The presence of metastases is an important prognostic factor that negatively affects survival. For (131)I-avid distant metastases, (131)I therapy is a very effective treatment modality that induces complete remission in about a third of patients. These figures may be even higher in case of early diagnosis, when tumor burden is still limited. Additional measures may include surgery and/or external beam radiation therapy. Cytotoxic chemotherapy is largely ineffective in patients with progressive, poorly differentiated cancer. These patients should be candidates for trials with new molecularly targeted therapeutic agents. In this paper, a review of diagnostic modalities, prognostic factors and therapeutic options for patients with distant metastases is proposed. In particular, the prognostic value of the early discovery of metastatic disease will be underlined.