Stereotactic multiple arc radiotherapy. I. Vascular malformations of the brain: an analysis of the first 108 patients

Abstract

Between March 1989 and December 1993, 101 patients with inoperable arteriovenous malformations (AVMs) and seven patients with inoperable angiographically occult malformations (AOVMs) have been treated with stereotactic multiple arc radiotherapy (SMART). All patients (excluding one patient with a brain stem AOVM) were treated with a uniform dose of 1750 cGy prescribed to the 90% isodose. Fifty-two patients with AVMs have had follow-up angiographic studies performed 11-42 months after SMART. The complete angiographic obliteration rates were 75-77% for AVMs 10 cm3 and 40-75% for AVMs 10 cm3, when studied 18-30 months after SMART. Four patients re-bled prior to complete obliteration representing an actuarial 2-year incidence of re-bleeding of 5.1%. Seven patients developed a new neurological deficit after SMART after a median latent interval of 17 months (range 6-32). The actuarial 2-year incidence of neurological complications was 1.8% for lesions 10 cm3. The actuarial 2-year incidence of neurological complications was 16% for lesions 10 cm3 (10.5% for persisting deficit). Of seven patients with AOVM six have shown a reduction in size and degree of contrast enhancement, but in no patient has there been complete resolution shown by CT. Five patients with AOVMs developed symptomatic neurological deterioration at a median of 6 months after SMART (range 5-9). When viewed in the context of the natural history of conservatively managed inoperable AVMs, this series has demonstrated that our highly specialized irradiation technique is a safe and effective treatment for many patients.

• Cerebral Arteriovenous Malformation;Linear Accelerator;Radiosurgery;Stereotaxis.