Safety of radiosurgery applied to conditions with abnormal tumor suppressor genes.

Objective: To assess the risk of radiosurgery inducing malignancy in neurofibromatosis-2 (NF2) and von Hippel-Lindau disease.

Methods: A retrospective cohort study of 118 NF2 and 19 von Hippel-Lindau disease patients, totalling 906 and 62 patient-years of follow-up data, respectively.

Results: Two cases of intracranial malignancy were identified, both of which occurred in NF2 patients. One of these was thought to have arisen before the radiosurgery; the other was a glioblastoma diagnosed 3 years after radiosurgery.

Conclusion: Because gliomas may occur in as many as 4% of NF2 patients, this may not represent an increased risk. We continue to offer radiosurgery treatment to selected NF2 and von Hippel-Lindau disease patients and consider that the late risk of malignancy arising after irradiation must be put in the context of the condition being treated, the treatment options available to these individuals, and their life expectancy.