Thyroid cancer and insulin resistance: is it important?

Abstract

Thyroid cancer (TC) has several distinct features. In particular, the median age on disease onset is about 45–50 years, which makes it quite different from hormonerelated tumors such as, for example, endometrial or prostate cancer. The prognosis of TC patients is relatively good in populations with differentiated carcinomas. However, it is worse in patients with medullary and anaplastic TC in particular. Prognosis is also poor in male patients, although in men thyroid cancer is seen thrice less often than in women and on average develops at a more advanced age. Besides female gender, there are other TC risk factors, such as radiation, iodine status of the area and excessive thyroid epithelium stimulation by thyrotropin (thyroid-stimulating hormone; TSH) [1]. Another important issue concerns the gradual increase in TC incidence, which has become particularly evident in the last decade. This increase is mostly due to a higher incidence of papillary carcinomas and could be explained by higher – than earlier – effectiveness of diagnostic methods (apparent increase) as well as greater number of new cases (true increase) [2]. The exact contribution of the latter factors is currently a matter of discussion. Our understanding of factors modulating TC incidence increase and mechanisms able to influence TCs clinical course was recently notably enhanced by the data concerned with a possible role of insulin resistance (IR) state. These ideas rely on two well-known facts, namely, on an established connection between IR and metabolic syndrome, some obesity types, and Type 2 diabetes mellitus incidence [3], and on the knowledge that the rate of the latter pathologies has lately reached ‘epidemic’ scale [4], which could also influence hormone-related cancers, such as TC. This short Editorial is mainly concerned with summarizing the current data on connections between IR and TC. The task is to try and point out some prominent aspects, in which these correlations seem to be most important, and describe possible approaches aimed at preventive as well as therapeutic antihormonal and metabolic interventions in TC patients, not limited only to ‘antithyroid’ (anti-TSH) measures.