Lenvima (Lenvatinib), a Multireceptor Tyrosine Kinase Inhibitor, Approved by the FDA for the Treatment of Patients with Differentiated Thyroid Cancer. (2015)

Thyroid cancer, cancer that starts in the thyroid gland, accounts for 3.8% of all cancer cases in the United States.1 There were an estimated 62,980 new cases of thyroid cancer and 1890 deaths resulting from thyroid cancer in 2014.1 Thyroid cancer is most common in people aged 45 to 54 years (median age, 50 years),1 and it occurs 2 to 3 times more often in women than in men.2 The incidence of thyroid cancer has risen steadily in recent years.3 Although this increasing rate can be attributed largely to disease detection at an earlier stage, the incidence of larger tumors has also increased.3

Thyroid cancer is classified into 3 types—differentiated (includes papillary, follicular, and Hurthle tumors); medullary tumors; and anaplastic (aggressive undifferentiated tumors).2 Differentiated thyroid cancer accounts for more than 90% of all cases of thyroid carcinoma.2

An estimated 566,708 patients were living with thyroid cancer in the United States in 2011.1 Approximately 68.2% of patients are diagnosed at the local stage of thyroid cancer; for patients with localized thyroid cancer, the 5-year survival rate is currently 99.9%.1 However, 10% to 30% of patients who are thought to be disease-free after the initial treatment will have disease recurrence and/or metastases.4 For patients with differentiated thyroid cancer that is refractory to radioactive iodine [131-isotope, also known as 131I] therapy, the 10-year survival rate is only 10% from the time that metastatic disease is detected.5,6

According to a recent study, the estimated annual US healthcare costs (undiscounted) for thyroid cancer were $1.4 billion in 2010; these costs are projected to reach $2.1 billion in 2015 and to exceed $3.1 billion by 2019.7 The authors noted that thyroid cancer is a major public health issue, particularly for women, given the increasing incidence (especially of papillary carcinoma) of the disease among women.7 According to another study, differentiated thyroid cancer accounted for total societal costs of approximately $1.6 billion annually in the United States in 2013.8 Furthermore, the annual costs attributable to differentiated thyroid cancer were projected to approach $3.5 billion by 2030 in that study.8

The treatment of differentiated thyroid cancer generally includes surgery, when possible, followed by radioactive iodine treatment in appropriate patients, and thyroxine therapy. Systemic therapy, including the recently approved tyrosine kinase inhibitors, may be used for patients with significant disease progression, nonresectable tumors, or tumors that are nonresponsive to radioactive iodine therapy.2

The multitargeted tyrosine kinase inhibitors have demonstrated a clinical benefit in locally recurrent, unresectable and metastatic medullary thyroid cancer and in radioactive iodine–refractory differentiated thyroid cancer.2 Optimal management of the side effects associated with tyrosine kinase inhibitor therapy and/or dose modification are key considerations when managing thyroid cancer with this class of drugs.2 The tyrosine kinase inhibitors represent an important advancement in the treatment of thyroid cancer, because they target multiple molecular pathways that are involved in the pathogenesis of thyroid tumors.5