Results of Proton Beam Radiosurgery in Cerebral Arteriovenous Malformations

Abstract

The routine use of microneurosurgical techniques has dramatically reduced the peri- and postoperative morbidity and mortality of patients harboring an arteriovenous malformation (AVM) of the brain [6, 18]. However, AVMs located in speech or deep areas of the brain or with a large size and/or high blood flow through the AVM nidus still represent a formidable challenge for the treating neurosurgeon. Stereotactic proton beam radiosurgery has been advocated for the treatment of AVMs of the brain that are considered to be of high surgical risk either due to their location in speech or deep areas of the brain or to their size [3, 4]. Because of excellent results of proton beam radiosurgery reported in the literature in the early 1980s [3], a group of 68 patients harboring high-risk cerebral AVMs were referred from our Department to a major radiosurgical center in the United States over a period of 10 years. However, intermediate and long-term follow-up revealed that in the vast majority of these patients the dimension of the AVM after radiation therapy remained virtually unchanged [11]. Additionally, the clinical symptoms present prior to radiation therapy did not show amelioration after radiosurgery in more than half of the patients, while deterioration due to hemorrhage from the radiated AVM, increased seizure frequency, progressive neurological deficits or as the result of radiation-induced leukencephalopathy developed in a considerable percentage of the patients.