LINAC radiosurgery treatment for vestibular schwannoma.

OBJECTIVE: The aims of our study were to evaluate tumour response in a series of patients with vestibular schwannoma (VS) treated with linear accelerator stereotactic radiosurgery (LINAC-RS), to describe the complications and to analyze the variables associated with the response to treatment.

MATERIAL AND METHODS: This retrospective descriptive study included 64 patients treated from 2010 to 2016 with a minimum follow-up of one year, excluding patients with neurofibromatosis. Clinical-radiological parameters were evaluated. The treatment was performed using LINAC-RS. The prescribed dose was 12Gy at 90% isodose.

RESULTS: The mean age at treatment was 53 years, 56% were women. Ninety-eight percent of the patients had hearing loss, 71% with grade III according to the Gardner-Robertson Classification. The mean volume at treatment was 2.92cc and the mean follow-up, 40.95 months. The overall therapeutic success was 90%, reaching 100% at 12 and 24 months, and 86% after 36 months of follow-up. The radiological result was significantly related to the initial tumour volume (p<0.037). In 20 patients there was evidence of transient tumour growth compatible with pseudoprogression. Acute complications were present in 37.5%, and transitory complications in 50%. Chronic complications were found in 20%, with 84% being permanent. The rate of acute complications was lower in patients with regression (p<0.016). Chronic complications were more frequent in the 41-60 year old age group (p<0.040).

CONCLUSIONS: In our study, the overall tumour control was in accordance with other published series. The radiological result significantly related to the tumour volume at the commencement of treatment. The rate of acute complications was lower in patients with regression.