[Thyroid cancer: prognostic factors and treatment].

Because most differentiated thyroid carcinomas have an excellent prognosis, some authors have claimed that these patients are suffering from over treatment. Grouping patient- and tumor-specific factors have been proposed for prognostic stratification, but no clinicopathologic staging was demonstrated to be useful at the present time. More recently, molecular genetic tools have been used to identify and understand how the primary tumor progresses and many molecular markers have been proposed in order to distinguish the subset of patients at risk of developing metastasis. Here we analyzed some of them, with emphasis on the expression of NIS, a determinant of prognosis since the functional integrity of the iodine transport is essential to assure an uptake of radioiodine high enough to detect and destroy any tumoral thyroid tissue. More recent observations on how some relevant molecular genetics aspects of thyroid cancer impact new potential therapeutic approaches are also discussed.