AbstractBackground and purposeFractionated stereotactic radiotherapy (FSRT) is an alternative treatment for large vestibular schwannomas (VS), if patients are not fit for or refuse surgery. In this study, we compared long-term clinical and radiological outcome in both small–medium sized and larger tumours.Material and methodsA retrospective study was performed of patients with sporadic VS who underwent primarily conventional FSRT. In total, 50 consecutive patients were divided into two groups by volume. Clinical and volumetric parameters were analysed.ResultsIn all, 41 patients (82%) had large tumours affecting the 4thventricle (modified Koos stage 4). Definitive expansion of VS occurred in eight out of 50 patients (16%). After 7·2 years (median) the overall freedom from clinical failure was 100% in smaller and 92% in larger schwannomas (arbitrarily sized >7·4 cc). Useful hearing was preserved in only 35% of the patients. The facial nerve remained intact in all cases, while new deficit of the trigeminal nerve occurred in 20% of the cases. Of the larger tumours 20% needed a cerebrospinal fluid (CSF) shunt.ConclusionsFSRT is a treatment in its own right as it is highly effective in both smaller and larger VS without causing permanent disabling complications. The outcome is beneficial also in larger tumours that affect the 4thventricle.