Malignant pheochromocytoma and paraganglioma
Pheochromocytomas and paragangliomas are neuroendocrine tumors originating in the paraganglia. Pheochromocytomas originate in the adrenal medulla, and paragangliomas originate in the extra-adrenal paraganglia. Most of these tumors secrete excessive amounts of catecholamines (adrenaline type hormones) that predispose patients to devastating complications (heart, blood vessels, abdomen, brain, kidneys, etc).
About 15% to 20% of these tumors are metastatic and cancerous, leading to a decreased overall survival. Whenever possible, the Mini Posterior Retroperitoneal Scope Adrenalectomy (Mini-PRSA) is the preferred adrenal surgery for >95 % of pheochromocytoma or paraganglioma.
Since this can be hard to say, our patients typically call it the Mini-Back-Scope-Operation. There are many reasons this minimally invasive technique is preferred over any of the other adrenal operations that can be done. The operation is performed with a scope and three small incisions lower part of the back of the patient. Since the adrenal glands are in the very back part of your abdomen, behind all the other organs, getting to them through the back with small scopes makes total sense and has many tremendous benefits--but few surgeons know how to do this--it is not taught in residency because no surgeons see enough cases of adrenal surgery to learn it.
However, occasionally, the malignant pheochromocytomas and paragangliomas are widespread and curative surgery is no longer possible. Currently, there are no systemic therapies approved by the European Medicines Agency or the US Food and Drug Administration (FDA) for patients with malignant pheochromocytoma and paraganglioma. Treatment options are limited to chemotherapy and low-specific activity 131meta-iodo-benzyl-guanidine (MIBG). Furthermore, toxicity associated with chemotherapy and radiopharmaceutical agents cannot be underestimated.
Tyrosine kinase inhibitors under evaluation in clinical trials Several tyrosine kinase inhibitors (TKIs), including axitinib, cabozantinib, lenvatinib, pazopanib, and sunitinib, are currently under evaluation in phase II clinical trials (www.ClinicalTrials.gov). These agents have in common their capacity to block the activation of the VEGF receptors (VEGFRs), preventing angiogenesis and cell growth. In addition, TKIs can inhibit other tyrosine kinase receptors that are universally involved in processes such as cancer cell growth, tumor spread, and development of resistance.