MDACC 2018: Updates in the Management of Malignant Pheochromocytoma/Paraganglioma

Houston, TX ( Paragangliomas are a group of tumors of the chromaffin cells and can originate from either the sympathetic or parasympathetic system. When the chromaffin cells originate from the sympathetic tissue of the adrenal medulla they are called pheochromocytes and give rise to pheochromocytomas.

These tumors have a favorable prognosis overall and can be treated with surgical resection in most cases, however, major morbidity is usually related to catecholamine hypersecretion. Delay in detection in a hypertensive patient can lead to long term irreversible cardiovascular damage. Metastatic disease is relatively uncommon (10-15%) but the 5-year overall survival (OS) is still fairly high at 60%. Removal of the primary tumor even for metastatic disease improves survival by eliminating the catecholamine excess and should be pursued when possible. Extra-adrenal paragangliomas carry a worse prognosis, especially when metastatic. Doxorubicin-based chemotherapy has an approximately 40% response rate1 but no clinicopathologic predictors of response have been identified.

Metaiodobenzylguanidine (MIBG) I-131 is a radiopharmaceutical that acts as a substrate for the norepinephrine pathway, delivering radioactive molecules directly to the tumor while also reducing its functionality. A newer agent, iobenguane I-131 is even more avid for the membrane transporter responsible for uptake into the tumor cells that have recently been approved by the FDA based on a phase 2b trial showing >50% reduction in tumor size in 25% of patients. Continued efforts to identify clinically active agents (i.e. cabozantinib, pazopanib, Lu177 dotate, HIF2 inhibitor) but data are too immature to draw definitive conclusions at this point.

Presented by: Jeena M. Varghese, MD, Department of Endocrine Neoplasia and Hormonal Disorders, University of Texas MD Anderson Cancer Center, Houston, TX, USA

1. Ayala-Ramirez, M., L. Feng, M.A. Habra, et al., Clinical benefits of systemic chemotherapy for patients with metastatic pheochromocytomas or sympathetic extra-adrenal paragangliomas: insights from the largest single-institutional experience. Cancer, 2012. 118(11): p. 2804-12.

Written by: Justin T. Matulay, MD and Ashish M. Kamat, MD, (@UroDocAsh), Professor, Department of Urology, Division of Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX at the 13th Update on the Management of Genitourinary Malignancies, The University of Texas (MDACC - MD Anderson Cancer Center) November 9-10, 2018, Dan L. Duncan Building, Houston, TX