Management of benign cranial nonacoustic schwannomas by fractionated stereotactic radiotherapy.

Schwannomas are the most common tumors of cranial nerves. Nonacoustic schwannomas are very rare tumors, accounting for approximately 10% of intracranial schwannomas. Standard treatment is complete surgical resection if possible. The role of fractionated stereotactic radiotherapy remains to be defined. Thirteen patients with cranial nonacoustic schwannomas underwent fractionated stereotactic radiotherapy. Seven patients had trigeminal schwannomas, three schwannomas of the lower cranial nerves, and three located in the cerebellopontine angle without involvement of the acoustic nerve. Treatment included primary or adjuvant radiotherapy in progressive disease. Tumor volume ranged from 4.5 to 76.0 cc (median 19.8 cc). Median dose was 57.6 Gy with 1.8 Gy/fraction. Median follow-up was 33 months (range 13-70 months). Local tumor control rate was 100% (13/13). Tumor size remained stable in nine patients and decreased in four. Improvement of preexisting neurological deficits was seen in four cases. No patient developed new cranial nerve or brain stem deficits. No patient showed clinically significant complications of irradiation. Fractionated stereotactic radiotherapy is an effective and well-tolerated noninvasive treatment for cranial nonacoustic schwannomas with excellent tumor control rates. It is an option for patients at higher risk for microsurgical resection or in residual and recurrent tumors. Copyright 2001 Wiley-Liss, Inc.