An internist's approach to cancer diseases based on the model of thyroid cancer treated with tyrosine kinase inhibitors.

925 New treatment options have come along the dis‐ covery of different tyrosine kinases and their cru‐ cial role in the pathogenesis of several cancers, in‐ cluding thyroid carcinoma. Multikinase inhibitors (MKIs) are a new group of drugs, recently widely in‐ vestigated in oncology. They show activity against receptors of different growth factors, leading to the inhibition of tumor cell growth and division. Thyroid cancer is the most common endocrine malignancy. According to the Polish National Can‐ cer Registry, it accounts for 0.5% and 2.6% of all neoplasms in men and women, respectively. The number of new cases of thyroid cancer has recently rapidly increased worldwide, mostly due to accurate and easily accessible thyroid sonogra‐ phy. In Poland, thyroid cancer was diagnosed in 314 patients in 1980, 448 patients in 1990, and as many as 2192 patients in 2010. The most common is differentiated thyroid cancer (DTC), diagnosed in nearly 94% of pa‐ tients (80%, papillary thyroid cancer [PTC] and 14%, follicular thyroid cancer [FTC]) and arising from follicular cells. Medullary thyroid carcino‐ ma (MTC), which develops from parafollicular C cells, accounts for 4% to 8% of all cases of thyroid cancer. In general, both DTC and MTC are char‐ acterized by good outcomes, with 10 ‐year over‐ all survival (OS) rates of 93%, 85%, and 75% for PTC, FTC, and MTC, respectively.1 Regardless of its good prognosis, approximate‐ ly 3% to 15% of DTC patients show disseminated disease at presentation,2,3 whereas DTC relapse may occur during decades in up to 30% of pa‐ tients.4 Surgery and/or radioiodine (RAI) thera‐ py are the main treatment options for recurrent DTC,5,6 as the majority of patients show the abil‐ ity of RAI uptake in cancer foci.7 However, one‐ ‐third of patients are refractory to RAI therapy. This group is characterized by much worse prog‐ nosis, with OS rates of about 10% at 10 years and 6% at 15 years.7 FORUM FOR INTERNAL MEDICINE