Radiation therapy in the treatment of chemodectomas.

Twenty-six patients with chemodectomas were treated with radiation therapy from 1961 to 1983 and followed for at least 4 years. In 16 glomus tympanicum lesions treated primarily with radiation, long-term control was achieved in all (follow-up 4-24 years, mean 10.5). Fifteen of 16 had no clinical evidence of disease at time of death or last follow-up, and one patient had recurrent but stable disease at 10 years and died of an unrelated illness 19 years after treatment. Eight of the glomus tympanicum lesions were referred for radiation therapy with persistent disease after multiple surgical procedures. Two had extensive skull and intracranial involvement at the time of radiation. Six patients with glomus jugulare lesions were treated with radiation. Four achieved long-term control, and two died of their disease. In addition, two glomus vagal and one carotid body tumor were treated with palliative intent. One glomus tympanicum lesion was treated with preoperative radiation and resection. Chemodectoma was the cause of death in 4 of 25 patients--3 from intracranial extension and 1 from lung and mediastinal metastases. All four patients were referred for radiation with metastases or extensive bone involvement at the skull base. Radiation appears to be effective in achieving long-term clinical control of chemodectomas. Adequately treated volume should be determined with arteriography and/or contrast-enhanced computer tomography, allowing for geometric margins. Doses in the range of 4,500 to 5,000 cGy delivered in about 5 weeks are recommended.