Fractionated Radiation Therapy in the Treatment of Cerebello-Pontine Angle Neurinomas: 12 Years of Experience in 29 Cases

Abstract

The purpose of this research was to reevaluate long-term results of frationated radiation therapy (RT) in two previously published series of cerebello-pontine angle (CPA) neurinomas. From January 1986 to October 1995, 29 patients with stage III and IV CPA neurinomas were treated with external fractionated RT. One patient was irradiated on both sides and indications for radiotherapy were as follows: (a) poor general condition or old age contraindicating surgery, 16 cases; (b) hearing preservation in bilateral neurinomas after contro-lateral tumor removal, 6 cases; (c) partial resection or high risk of recurrence after subsequent surgery for relapse, 5 cases; (d) nonsurgical relapse, 3 cases. Most patients were irradiated with 6 to 10 MV photons. A three- to four-field technique with coplanar static beams and conformal blocks was used. Doses were calculated on a 95% isodose and were given 5 days a week for a mean total dose of 51 Gy (1.80 Gy/fraction). Median follow-up from RT was 66 months (7 to 120); 7 patients died, 2 with progressive disease, 5 from nontumoral causes. Two patients underwent total tumor removal after RT (1 stable and 1 growing tumor). On the whole, tumor shrinkage was observed in 13 patients (43.3%), stable disease in 14 (46.6%), and tumor progression in 3. Hearing was maintained in 4 out of 6 hearing patients. No patient experienced facial or trigeminal neuropathy. Long-term efficacy of fractionated RT is well documented in this series. Acute and delayed tolerance was excellent. Hearing can be preserved for a long time.