Optimum dose of radiotherapy for chemodectomas of the middle ear

Forty patients with chemodectomas of the middle ear were seen at the University of Virginia Hospital from 1932 to 1978. Surgery, post-operative radiotherapy or radiotherapy alone were the treatment modalities employed depending on the extent of the disease. These have been reviewed with regard to the clinical presentation and results of treatment with long term follow-up of 1 to 30 years. An attempt was made to determine the optimum dose of radiotherapy based on our data and reported cases in the literature. The majority of patients complaining of tinnitus, otalgia and pulsation obtained significant if not complete relief of symptoms. Cranial nerve defects, however, ofter persisted after therapy. Tumor was considered to be controlled if there was no increase in its size or progression of symptoms. Tumor control was obtained in eight of 10 early patients but only in two of seven more patients with advanced disease with total resection. Control rate with post-operative radiotherapy after subtotal resection was 85%. Radiotherapy alone was used for inoperable or recurrent tumors and control was obtained in 88% of them. In addition to our data, the radiation dose used in over 200 patients reported in the literature was analyzed. There was only a 2% recurrence rate in patients who received 4000 rad/4 weeks or higher. Twenty-two percent of patients treated with less than 4000 rad developed recurrence. The tendency is to use a lower dose of postoperative treatment and a higher dose for gross inoperable tumors. 4000 rad/4 weeks seems to be adequate for control of postoperative residual disease and no more than 5000 rad/5 weeks are required even for advanced inoperable cases. By keeping the dose below 5000 rad/5 weeks, the incidence of complications such as brain necrosis is greatly decreased