Long-term outcome after highly advanced single-dose or fractionated radiotherapy in patients with vestibular schwannomas - pooled results from 3 large German centers.

PURPOSE: To evaluate long-term clinical outcome and determine prognostic factors for local-control, hearing preservation and cranial nerve toxicity in 449 patients treated for 451 vestibular schwannomas (VS) with radiosurgery (n=169; 38%) or fractionated stereotactic radiotherapy (FSRT; n=291; 62%). METHODS AND MATERIALS: 245 patients were male (55%), and 204 were female (45%). Median age was 60years (range 17-88years). Median tumor diameter was 15mm. For FSRT, a median dose of 57.6Gy in median single doses of 1.8Gy was applied. For SRS, median dose was 13Gy. The median follow-up time was 67months. RESULTS: Local control was 97% at 36months, 95% at 60months, and 94% at 120months with no difference between FSRT and SRS (p=0.39). "Useful hearing" was present 46%. After RT, "useful hearing" was preserved in 85% of the patients. Loss of useful hearing was observed in the FSRT group in 14%, and in the SRS group in 16% of the patients. For patients treated with SRS ⩽13Gy, useful hearing deterioration was 13%. For trigeminal and facial nerve toxicity, there was no difference between FSRT and SRS. CONCLUSION: Supported by this large multicentric series, both SRS and FSRT can be recommended for the treatment of VS. SRS application is limited by tumor size, and is associated with a steep dose-response-curve. When chosen diligently based on tumor volume, pre-treatment characteristics and volume-dependent dose-prescription in SRS (⩽13Gy), both treatments may be considered equally effective