Tyrosine Kinase Inhibitors and Thyroid Toxicity

Some multithyrosine kinase inhibitors have been reported to cause changes in thyroid function. For the management of sunitinib-induced hypothyroidism, an evaluation of thyroid hormone and antibody profile is recommended before starting treatment with tyrosine kinase inhibitors. Patients with pre-existing thyroid dysfunction should undergo dose adjustment of L-thyroxine during treatment with tyrosine kinase inhibitors. Thyroid dysfunction is not a reason to discontinue or reduce the dosage of sunitinib. Their occurrence appears to correlate with increased antitumour efficacy of the inhibitor. There are currently no guidelines for monitoring thyroid activity during treatment with TKIs, and the time interval at which TSH should be periodically measured has not yet been determined. A reasonable approach is to monitor thyroid function, both before and during 2-4 weeks after the end of therapy. A comprehensive analysis of adverse events associated with the use of these inhibitors could help clinical monitoring of patients along with the adoption of appropriate management approaches.