Metastatic Medullary Thyroid Carcinoma and Cabozantinib: Case Series and Review of Literature

Cabozantinib, a tyrosine kinase inhibitor, was approved by the US Food and Drug Administration in November 2012, for the treatment of metastatic medullary thyroid carcinoma. Although side effects typically include stomatitis, palmar-plantar erythrodysesthesia syndrome, hypertension and diarrhea, most patients are able to tolerate the recommended dose of 140 mg daily. Surgical resection is the primary treatment for medullary thyroid carcinoma. Patients with metastatic disease, who are not candidates for surgery, are considered candidates for systemic therapy. However, systemic chemotherapy has a limited role in metastatic disease. Our paper highlights not only the malignant potential of a medullary thyroid carcinoma, but also the role of cabozantinib in patients with progressive metastatic disease. We report two cases of patients with progressive metastatic medullary thyroid carcinoma (involving lung, lymph nodes, liver, pancreas, brain and spine) who responded well to therapy with cabozantinib.