External-beam radiation therapy for malignant paraganglioma of the head and neck

Malignant paragangliomas of the head and neck are very rare tumors of the neuroendocrine cells associated with the peripheral nervous system. There are limited data available to help guide treatment of these tumors and the role of radiation therapy (RT) is not well-defined. This article briefly reviews the pathology, clinical presentation, and treatment modalities of these tumors and reviews our institutional experience in treating this malignancy.

From November 1993 through May 2005, 5 patients with 5 malignant paragangliomas of the jugular bulb and carotid body were treated with RT at the University of Florida to a median dose of 70 Gy at 1.8 Gy per fraction. Mean and median follow-up times are 12.8 years and 14.4 years, respectively.

We were able to achieve significant disease-free intervals of >10 years for 3 of 5 patients and >5 years for 4 of 5 patients. Of the 2 patients who failed treatment, 1 recurred 7.3 years after the RT salvage treatment following combination surgery and RT at another institution, and 1 experienced distant metastasis 2.8 years after treatment without obvious recurrence of local disease.

Malignant paragangliomas are a very rare entity whose main treatment modality has yet to be well established. Overall, data concerning outcomes are sparse, but particularly data on the role of RT in the treatment of these difficult tumors. We recommend doses to 70 Gy at 2 Gy per once-daily fraction as an adjuvant treatment with surgery to both remove the source of disease and provide microscopic control. Patients with incompletely resectable tumors are treated with RT alone.