Dr. Young: The follow-up once you’ve resected an adrenal pheochromocytoma depends on whether there is a germline mutation. If there is a germline mutation, for example, succinate dehydrogenase mutation [SDH], these patients are at higher risk for developing recurrent pheochromocytoma or paraganglioma, and they’re at risk for developing malignant pheochromocytoma or paraganglioma.
One of our challenges is when we resect a pheochromocytoma or paraganglioma, the pathologist doesn’t have the tools to tell us if it’s benign or malignant ... So all patients need lifelong biochemical follow-up, basically a 24-hour urine for metanephrines and catecholamines annually or plasma metanephrines for life.
If the patients have an underlying mutation like succinate dehydrogenase, they’re at risk for developing nonfunctioning paragangliomas. So these patients need periodic imaging in addition to the annual biochemical testing. For example, if a patient had an abdominal paraganglioma with an SDHB [succinate dehydrogenase complex iron sulfur subunit B], we would do abdominal MRI scans every 1-2 years. That would include the pelvis. We would screen for paragangliomas elsewhere with MRI of the skull base and neck and the chest every 3-5 years, and a total body scan every 5 years or so, either FDG-PET [18F-fluorodeoxyglucose positron emission tomography] scan or 123I-MIBG [metaiodobenzyl-guanidine] scan.
FMN: Is there anything that is particularly new in the past couple of years?
Dr. Young: Some of the innovations lately have been in the area of metastatic pheochromocytoma and paraganglioma. These are in patients who have limited metastatic disease that’s localized to bone or to liver, and we’ve been using ablative therapies. This includes cryoablation ... and radiofrequency ablation, which is killing the tumor with hot temperature, and that’s very effective for patients who have limited metastatic lesions in the bone or liver.
For patients with complex tumors in difficult areas of the body, for example, in the mediastinum or surrounding the heart, we’ve been using 3D printer technology to print [a replica of the structures and] the tumor preoperatively, and this assists in surgical planning.
FMN: And what do you see coming?
Dr. Young: I think we’re getting close to something near curative for patients with malignant pheochromocytoma and paraganglioma. We’re understanding the basic biology better [and] pathophysiology, and I think that’s going to lead to some novel treatments.
Also, what I see coming is that we’ll be able to use germline mutation information and somatic tumor mutation information to guide us on specific imaging modalities, to guide us on forms of preventative therapy so that we prevent the paraganglioma from ever developing and also provide us with additional treatment options.