How effective is radiosurgery for arteriovenous malformations?
- The Institute of Cancer Research and The Royal Marsden NHS Trust, Downs Road, Sutton, Surrey SM2 5PT, UK
- The National Hospital for Neurology and Neurosurgery, London
- Dr Michael Bradambrada{at}icr.ac.uk
- The Institute of Cancer Research and The Royal Marsden NHS Trust, Downs Road, Sutton, Surrey SM2 5PT, UK
- The National Hospital for Neurology and Neurosurgery, London
- Dr Michael Bradambrada{at}icr.ac.uk
Complete surgical excision is the treatment of choice for accessible arteriovenous malformations (AVMs). Non-invasive alternatives of radiosurgery and embolisation are generally offered to patients with inaccessible AVMs with the hope of equivalent effectiveness and low morbidity. Kurita et al in this volume (pp563–570)1 advocate radiosurgery as a “viable” treatment modality for brainstem AVMs which is “safe and effective” for small lesions. Do we really have a cure for previously untreatable AVMs? Let us examine the evidence for the risks and benefits of this treatment technique.
Radiosurgery refers to single high dose localised irradiation, given using either a gamma unit (gamma knife, multiheaded cobalt unit) or a linear accelerator (linac radiosurgery, X-knife radiosurgery). It aims to destroy blood vessels of the AVM nidus, while avoiding injury to normal brain and this is achieved by focusing radiation onto the lesion. The effectiveness of radiosurgery is generally measured in terms of disappearance of abnormal blood vessels on angiography. After radiosurgery, the rate of angiographic obliteration increases with time and is size and radiation dose dependent. The reported obliteration rates at 2 years are in the region of 80% to 90% for small lesions (<2 cm diameter) and 40% to 60% for larger lesions. There is however, some concern about the …
