Radiosurgery for Large Arteriovenous Malformations as a Single-Session or Staged Treatment

Abstract

Background/Objectives: The treatment of large arteriovenous malformations (AVMs) presents a challenge and the effectiveness of radiosurgery decreases with increasing treatment volume. Here, we analyzed and compared single-session treatment for AVMs >15 cm³ with staged treatment, when the volume of a large AVM was divided into 2 or more compartments, which were subsequently treated at intervals of a few months. In the event that complete obliteration was not achieved within 3 years, repeat radiosurgery was considered. Methods/Results: Between 1993 and 2011, gamma-knife radiosurgery was performed on 50 patients with large AVMs. A total of 27 of them, with volumes ranging from 15.1 to 27 cm³ (median = 17.8), were treated in a single session, with a marginal dose ranging from 10 to 17 Gy (median = 15). Complete obliteration was achieved in 7 (26%) of these; in 14 patients the treatment was repeated after a median of 38 months. The volume of AVMs subjected to repeat treatment regressed and ranged from 6.76 to 16.4 cm³ (median = 7.7), with the marginal dose ranging from 13 to 18 Gy (median = 17); 10 patients later achieved complete obliteration at a median of 79 months after the initial treatment. Overall, 63% of patients achieved complete obliteration of AVM after treatment. Rebleeding in a latent period was recorded in 3 patients (11%) and symptomatic collateral edema in 2 (7%); 23 patients were treated using the staged method, with the interval between staged treatments usually being 6 months. Their overall AVM volume ranged from 13.2 to 46.6 cm³ (median = 23.3), the volume for a single stage ranged from 4.5 to 31.3 cm³ (median 11.7), and the marginal dose ranged from 10 to 18 Gy (median = 17). Complete obliteration was achieved in 4 (17%) of them, in 8 patients the treatment was repeated at a median of 53 months after the first treatment, and a third retreatment was performed on 2 patients 98 and 102 months, respectively, after the first treatment. The volume for repeated treatment of AVMs ranged from 0.81 to 7.7 cm³ (median = 3.3), with the marginal dose ranging from 14 to 20 Gy (median 17.5). Of all the retreated patients, 5 AVMs subsequently achieved complete obliteration. Overall, 9 patients (39%) were totally cured. Rebleeding in a latent period was observed in 1 of these patients (4.3%) and symptomatic edema in another 1 (4.3%). Conclusions: Radiosurgery of large AVMs is a valuable treatment either as a single-session or staged treatment, with a reasonable chance of cure and a low risk of complications.

Radiosurgery for Cerebral Arteriovenous Malformation (AVM) : Current Treatment Strategy and Radiosurgical Technique for Large Cerebral AVM

“…Dose-volume relationship can be unfavorable for large AVMs when treated in a single-session radiosurgery, resulting high complication rates for effective dose 15,17) . In large AVM, reported obliteration rate is low (less than 50%) and large area of irradiated normal tissue adjacent AVM could increase radiation-induced complication 10,11,16) . For this reason, single-session radiosurgery could not be a good treatment option of higher grade AVM (Spetzler-Martin grade III-V).…”

Gamma Knife treatment strategies for paediatric AVMs: approaches to refractory cases

“…Post-treatment oedema occurs in 20-30% of patients and dose-staged radiosurgery, in which the target is the entire AVM and the dose is lowered according to the irradiated volume, is often conducted. 11,25 Since the low-dose region volume increases proportionally with the treatment volume in stereotactic radiotherapy, a lower treatment dose can be said to reduce the occlusion rate and, simultaneously, increase the possibility of requiring repeated irradiation. This will further increase the incidence of radiation injury and compromise the flexibility of the surrounding brain tissue for later hemodynamic changes.…”

Radiosurgery: Fair Treatment Option for Inoperable Brain Vascular Lesions

“…Radiosurgery is thus humbly applied to select patients who could be healed without unacceptable risks. The chance to cure large AVMs after staged radiosurgery is 39% [2]. Statistically, the risk of rebleeding is reduced for cavernomas after the latency period [3].…”