Fractionated stereotactic radiotherapy for bilateral vestibular schwannomas associated with neurofibromatosis type 2: early experiences in Ramathibodi Hospital.

PURPOSE

To evaluate the rates of tumor control and useful hearing preservation in patients with bilateral vestibular schwannomas (VSs) associated with neurofibromatosis type 2 (NF-2) treated with fractionated stereotactic radiotherapy (FSRT).

MATERIAL AND METHOD

From August 1998--December 2002 there were 5 patients with NF-2 who underwent FSRT (Linac-based system) for bilateral CP angle tumors. Median age was 28 (18-47) years. Median tumor volume was 5.4 (2.2-9.4) cc. Eight lesions received a marginal dose of 44.2-59.9 (median = 46.2) Gy in 25-33 fractions. The other 2 lesions received 4.4 and 4.9 Gy/fraction for 6 fractions in 3 and 2 weeks. Median follow-up was 19 (14-44) months.

RESULTS

Radiographic and clinical tumor control rate was 90%. One lesion progressed at 7 months after FSRT and was completely resected Of the 5 lesions with Gardner-Robertson class I-II hearing before FSRT 2 (40%) retained useful hearing at the last follow-up. One patient had left facial spasm at 10 months after FSRT which gradually improved. No patient had facial palsy, facial numbness or pain.

CONCLUSIONS

FSRT provided good tumor control and hearing preservation rate in NF-2 patients with minimal morbidity. However, a longer follow-up is needed to evaluate long term results.