Endocrine malignancies, although relatively uncommon, are often difficult to diagnose and treat effectively. This chapter will focus on thyroid and parathyroid cancers. (A discussion of carcinoid tumors, insulinomas, gastrinomas, and other gastrointestinal neuroendocrine tumors, as well as adrenocortical cancer, can be found in the "Pancreatic, Neuroendocrine GI, and Adrenal Cancers" chapter.)
In November 2012, the US Food and Drug Administration (FDA) approved the tyrosine kinase inhibitor cabozantinib (Cometriq) for the treatment of metastatic medullary thyroid cancer. The EXAM trial, a 330-patient clinical trial that led to its approval, randomized patients in a 2:1 ratio to cabozantinib at 140 mg daily (n = 219) or to placebo (n = 111). The study found that cabozantinib increased progression-free survival compared with placebo, 11.2 months vs 4 months, respectively (hazard ratio [HR] = 0.28; 95% confidence interval [CI], 0.19–0.40; P < .001). Reductions in tumor size lasting an average of nearly 15 months were seen in 27% of patients treated with cabozantinib.