Antiangiogenic therapies for pheochromocytoma and paraganglioma.

Metastatic pheochromocytomas and paragangliomas are rare, highly vascular tumors that spread primarily to the lymph nodes, skeletal tissue, lungs, and liver. Tumor morbidity is related to their size, location, hormonal activity, vascular nature, and rate of progression. Systemic therapies for this indication are limited. Only high-specific-activity iodine-131 metaiodobenzylguanidine is approved in the Unites States for treatment of these patients, and not all patients are candidates for this radiopharmaceutical. Antiangiogenic medications are currently being evaluated in prospective clinical trials for patients with metastatic pheochromocytomas and paragangliomas, and preliminary results have been encouraging. Antiangiogenic medications frequently offer antineoplastic effects with sometimes durable responses. However, cardiovascular toxicity and the development of tumor resistance may limit their efficacy. Experience derived from clinical trials is being used to identify mechanisms to effectively improve drug toxicity and possibly prevent the emergence of resistance. Therefore, antiangiogenic medications represent a therapeutic option for patients with metastatic pheochromocytomas and paragangliomas. Furthermore, in the world of oncology, there is strong scientific interest in the development of clinical trials that combine antiangiogenic medications with other modalities such as immunotherapy, radiopharmaceuticals, and hypoxia inhibitors since these combinations may substantially enhance clinical outcomes, including survivorship. In this review, we examine the progress made to date on antiangiogenic treatments for patients with metastatic pheochromocytomas and paragangliomas.