Thyroid cancer incidence has significantly increased in the last three decades and many patients seek medical attention for its treatment every year. Among follicular cell-derived tumors, the majority are differentiated thyroid carcinomas (DTC), whose prognosis is very good with only 15% of the cases presenting disease persistence or recurrence after initial treatment. Medullary thyroid carcinoma has a worse prognosis, especially in patients with diffused cancers at the time of initial surgery. Traditional treatment options for persistent or recurrent disease include additional surgery, radioiodine treatment and TSH-suppression in DTC patients; external beam radiotherapy, and cytotoxic chemotherapy, often have low efficacy and many patients with advanced disease ultimately die. In the last two decades many of the molecular events involved in cancer formation have been uncovered. This knowledge has prompted the development of novel therapeutic strategies mainly based on the inhibition of key molecular mediators of the tumorigenic process. In particular the class of small-molecule tyrosine kinase inhibitors was enriched by many compounds that have reached clinical trials and in some cases have had approval for clinical use in specific cancers. Many of these compounds entered clinical trials also for locally advanced or metastatic thyroid carcinomas showing very promising results. Arq Bras Endocrinol Metab. 2009;53(9):1061-73 Keywords Thyroid carcinoma; radioiodine therapy; external beam radiation therapy; cytotoxic chemotherapy; targeted therapies; tyrosine kinase inhibitors ReSumo O cĂąncer de tireoide tem aumentado significativamente nas Ășltimas trĂȘs dĂ©cadas e muitos pacientes tĂȘm buscado cuidados mĂ©dicos para o tratamento a cada ano. Entre os tumores derivados de cĂ©lulas foliculares, a maioria Ă© carcinoma diferenciado de tireoide (CDT), cujo prognĂłstico Ă© muito bom, em que somente em 15% dos casos a doença Ă© persistente ou recorrente apĂłs o tratamento inicial. O carcinoma medular de tireoide tem um prognĂłstico pior, especialmente em pacientes com cĂąncer difuso no momento da cirurgia inicial. As opçÔes no tratamento tradicional para a doença persistente ou recorrente incluem cirurgia adicional, radioiodoterapia e supressĂŁo de TSH em pacientes CDT; a radioterapia externa e a quimioterapia citotĂłxica apresentam com frequĂȘncia uma baixa eficĂĄcia e muitos pacientes com doença avançada nĂŁo sobrevivem. Nas Ășltimas duas dĂ©cadas, muitos dos eventos envolvidos na formação do cĂąncer tornaram-se conhecidos. Esse conhecimento possibilitou o desenvolvimento de novas estratĂ©gias terapĂȘuticas, baseadas principalmente na inibição de mediador molecularchave no processo tumorigĂȘnico. Em particular, a classe das pequenas molĂ©culas inibidoras de tirosina-quinase foi enriquecida por muitos compostos investigados em estudos clĂnicos e alguns casos foram aprovados para uso clĂnico em tipos especĂficos de cĂąncer. Muitos desses compostos foram aplicados em estudos clĂnicos de cĂąncer de tireoide com extensa invasĂŁo local ou metĂĄst...