Tyrosine kinase inhibitors and modifications of thyroid function tests: a review

Tyrosine kinase inhibitors (TKI) belong to new molecular multi-targeted therapies that are approved for the treatment of haematological and solid tumours. They interact with a large variety of protein tyrosine kinases involved in oncogenesis. In 2005, the first case of hypothyroidism was described and since then, some data have been published and have confirmed that TKI can affect the thyroid function tests (TFT). This review analyses the present clinical and fundamental findings about the effects of TKI on the thyroid function. Various hypotheses have been proposed to explain the effect of TKI on the thyroid function but those are mainly based on clinical observations. Moreover, it appears that TKI could alter the thyroid hormone regulation by mechanisms that are specific to each molecule. The present propositions for the management of TKI-induced hypothyroidism suggest that we assess the TFT of the patients regularly before and during the treatment by TKI. Thus, a better approach of patients with TKI-induced hypothyroidism could improve their quality of life.