Gamma knife radiosurgery for intracranial haemangioblastomas

Background. The results of gamma knife radiosurgery for haemangioblastomas were retrospectively studied to assess the efficacy for tumour growth control and clarify the clinical indications for gamma knife radiosurgery in these tumours. Methods. The medical records of 22 patients with 67 tumours, 12 men and 10 women aged 20-73 years (mean 51.9 years), who underwent gamma knife radiosurgery for haemangioblastomas between January 1993 and January 2006, were retrospectively reviewed. Ten patients with 54 lesions had von Hippel-Lindau disease. The mean tumour volume was 1.69 cm(3) (range 0.0097-16.4 cm(3)). Nineteen patients had undergone 1-4 open surgery procedures (mean 1.5) before gamma knife radiosurgery. Tumours without a cystic component, (the solid type), were found in 54 lesions and tumours associated with cyst, (the mural nodule with cyst type), in 13 lesions. The marginal dose was 8-30 Gy (mean 14.0 Gy). Findings. Follow-up magnetic resonance (MR) imaging was performed at 9-146 months (mean 63 months). The control rate for tumour growth was 83.6%. The only factor affecting tumour growth control was the presence of a cystic component at the time of gamma knife radiosurgery in both univariate and multivariate analysis. No complication such as radiation-induced peritumoural oedema or radiation necrosis occurred. Conclusion. The presence of cystic components at the time of gamma knife radiosurgery was the only factor significantly correlated with unfavourable tumour growth control by gamma knife radiosurgery for haemangioblastomas. Gamma knife radiosurgery is effective for solid type tumours, even if the marginal dose is relatively low. Surgical removal is recommended for mural nodule with cyst type tumours, when possible.