External beam radiation therapy in treatment of malignant pheochromocytoma and paraganglioma.

Jennifer Vogel,Aradhana Kaushal,Tamara Prodanov,Karen Adams,Baris Ismail Turkbey,Antonio Tito Fojo,Aileen Sia Atanacio,Victoria Martucci,Kevin Camphausen,Karel Pacak

doi:10.3389/fonc.2014.00166

Abstract

Purpose: Pheochromocytomas (PCCs) are neuroendocrine tumors arising from the adrenal medulla or as paraganglioma (PGL) from extra-adrenal sites. While usually benign, a small fraction is malignant. Multi-modality therapy is used in treating malignant disease; however, little data exist on the role of external beam radiation therapy (EBRT). In this retrospective review, we assessed response to EBRT in malignant PCCs or PGLs.Methods and Materials: Records of patients treated at the National Institutes of Health who received EBRT between 1990 and 2012 were studied. Patients were assessed for symptomatic control, biochemical response, local and distant control by response evaluation criteria in solid tumors v1.1 or stable disease on imaging reports, toxicity by radiation therapy oncology group (RTOG) criteria, and survival.Results: There were 24 patients treated who received EBRT to lesions of the abdomen (n = 3), central nervous system (n = 4), and bone (n = 40). Lesions were treated with 3D conformal EBRT to a mean dose of 31.8 Gy in 3.3 Gy fractions, or fractionated stereotactic radiosurgery to 21.9 Gy in 13.6 Gy fractions. Patients experienced acute (n = 15) and late (n = 2) RTOG toxicities; no patient experienced acute toxicity ≥4 or late toxicity ≥2. Symptomatic control was achieved in 81.1% of lesions. Stable radiographic response was achieved in 86.7% of lesions with progression in 13%. Distant progression was observed overall in 75% of patients and average survival was 52.4 months.Conclusion: Malignant PCC and PGL often do not respond well to current systemic therapies. In these cases, EBRT can be considered in patients with symptomatic, localized disease progression.

Highlights

Pheochromocytomas (PCCs) are neuroendocrine tumors arising from chromaffin cells of the adrenal medulla
Lesions were treated with 3D conformal external beam radiation therapy (EBRT) to a mean dose of 31.8 Gy in 3.3 Gy fractions, or fractionated stereotactic radiosurgery to 21.9 Gy in 13.6 Gy fractions
Radiographic response was determined by response evaluation criteria in solid tumors (RECIST) v1.1 based on computed tomography (CT) or magnetic resonance imaging (MRI) reports for a subset of eight patients with 12 lesions with pre and posttreatment imaging available for evaluation (Figure 1)

Summary

Introduction

Pheochromocytomas (PCCs) are neuroendocrine tumors arising from chromaffin cells of the adrenal medulla. Adrenal PCCs are the most common chromaffin tumors, occurring in about 80–85% of cases. As PGLs, which may be classified as branchiomeric, including glomus jugulare and carotid body tumors; intravagal; aorticosympathetic; and visceral-autonomic. These tumors are rare, with an annual reported incidence of two to eight per million population and prevalence in 0.2–0.4% of hypertensive patients. They are characterized by their ability to synthesize, store, and secrete catecholamines some, especially those of branchiomeric or intravagal origin, are non-functional. Less sensitive for diagnosis, chromogranin A levels are valuable in following response to therapy and monitoring for recurrence [1]

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Results