Original Contributions
Five year results of linac radiosurgery for arteriovenous malformations: outcome for large AVMS

Oral presentation at the 39th Annual Scientific Meeting of the American Society for Therapeutic Radiology and Oncology, October 19–22, 1997, Orlando, Florida.
https://doi.org/10.1016/S0360-3016(99)00102-9Get rights and content

Abstract

Purpose: For radiosurgery of large arteriovenous malformations (AVMs), the optimal relationship of dose and volume to obliteration, complications, and hemorrhage is not well defined. Multivariate analysis was performed to assess the relationship of multiple AVM and treatment factors to the outcome of AVMs significantly larger than previously reported in the literature.

Methods and Materials: 73 patients with intracranial AVMs underwent LINAC radiosurgery. Over 50% of the AVMs were larger than 3 cm in diameter and the median and mean treatment volumes were 8.4 cc and 15.3 cc, respectively (range 0.4–143.4 cc). Minimum AVM treatment doses varied between 1000–2200 cGy (median: 1600 cGy).

Results: The obliteration rates for treatment volumes < 4 cc, 4–13.9 cc, and ≥ 14 cc were 67%, 58%, and 23%, respectively. AVM obliteration was significantly associated with higher minimum treatment dose and negatively associated with a history of prior embolization with particulate materials. No AVM receiving < 1400 cGy was obliterated. The incidence of post-radiosurgical imaging abnormalities and clinical complications rose with increasing treatment volume. For treatment volumes > 14 cc receiving ≥ 1600 cGy, the incidence of post-radiosurgical MRI T2 abnormalities was 72% and the incidence of radiation necrosis requiring resection was 22%. The rate of post-radiosurgical hemorrhage was 2.7% per person-year for AVMs with treatment volumes < 14 cc and 7.5% per person-year for AVMs ≥ 14 cc.

Conclusion: As AVM size increases, the dose-volume range for the optimal balance between successful obliteration and the risk of complications and post-radiosurgical hemorrhage narrows.

Introduction

Stereotactic radiosurgery is an effective and safe treatment for small intracranial arteriovenous malformations (AVMs). Most series in the radiosurgery literature have median AVM volumes between 1–4 cc (equivalent diameter 1–2 cm) with the majority of volumes treated being smaller than 14 cc (equivalent diameter < 3 cm). For these small AVMs, 2–3 year obliteration rates between 72–96% have been reported with associated complication rates between 1–10% 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. There is only limited data for larger AVMs, and the results are conflicting with reported obliteration rates varying between 0–75% and complication rates varying between 3–50% 1, 3, 4, 7, 9, 10, 15, 18, 19, 20, 21, 22, 23, 24. For large AVMs, the optimal dose-volume relationship remains poorly defined as does the ideal integration of staged procedures, embolization, surgery, and re-irradiation 21, 23, 25, 26. The following report is a retrospective study of factors affecting the long-term outcome of LINAC radiosurgery for patients with AVMs larger than previously published in the literature. Over 50% of the AVMs were larger than 3 cm in diameter, and the median and mean treatment volumes were 8.4 cc and 15.3 cc, respectively.

Section snippets

Patients

Between March 1988 and September 1991, 73 consecutive patients with intracranial AVMs underwent LINAC radiosurgery at the University of California at San Francisco (UCSF). Table 1 summarizes their clinical characteristics. Forty-six patients (63%) had a prior history of hemorrhage from their AVMs including 13 who had suffered multiple hemorrhages (range 0–4). Fifty-six patients (77%) had a history of focal neurologic symptoms, and 41 (56%) had a focal neurologic deficit at the time of

Follow-up

Six years after the last patient was treated, 46 patients (63%) reached one of the following endpoints (Fig. 1, Fig. 2 ) : 18 (25%) had AVM obliteration documented by angiography; 10 (14%) had AVM obliteration documented by MRI/MRA with angiographic confirmation either pending or refused; 7 (10%) were retreated with radiosurgery; 2 (3%) underwent surgery; 5 (7%) died of an intracranial hemorrhage; 1 (1%) died of treatment related complications; 3 (4%) died of intercurrent disease. The

Discussion

The AVMs treated in this study were significantly larger than those in other series in the literature. Over 50% were larger than 3 cm in diameter, and the median and mean treatment volumes were 8.4 cc and 15.3 cc, respectively. Furthermore, the volumes reported represent post-embolization volumes and do not reflect the large initial volumes prior to down-staging with embolization 21, 23, 36. Fifty-nine percent underwent prior embolization, a rate much higher than the 1–39% reported in other

Conclusions

With radiosurgery, successful outcomes are possible for patients with large AVMs otherwise not amenable to definitive therapy. However, effective and safe treatment requires the appropriate selection of patients, accurate imaging and definition of the AVM nidus, optimal planning and treatment techniques, proper selection of dose, and careful follow-up. As AVM size increases, the dose-volume range for optimal balance between successful obliteration and the risk of complications and

References (86)

  • W.Y. Guo et al.

    Gamma knife surgery of cerebral arteriovenous malformationsSerial MR imaging studies after radiosurgery

    Intl Radiol Oncol Biol Phys

    (1993)
  • F.J. Bova et al.

    Stereotactic angiographyan inadequate database for radiosurgery?

    Int J Radiat Oncol Biol Phys

    (1991)
  • R. Foroni et al.

    Shape recovery and volume calculation from biplane angiography in the stereo tactic radiosurgical treatment of artenovenous malformations

    Int J Radiat Oncol Biol Phys

    (1996)
  • D. Petereit et al.

    Treatment of arteriovenous malformations with stereotactic radiosurgery employing both magnetic resonance angiography and standard angiography as a database

    Int J Radiat Oncol Biol Phys

    (1993)
  • J.C. Flickinger et al.

    Dose prescription and dose-volume effects in radiosurgery

    Neurosurg Clin N Am

    (1992)
  • J.C. Flickinger et al.

    Complications from arteriovenous malformation radiosurgery.. multivariate analysis and risk modeling

    Int J Radiat Oncol Biol Phys

    (1997)
  • D.A. Larson et al.

    The radiobiology of radiosurgery

    Int J Radiat Oncol Biol Phys

    (1993)
  • J. Voges et al.

    Risk analysis of linear accelerator radiostirgery

    Int J Radial Oncol Biol Phys

    (1996)
  • M. Yamamoto et al.

    Gamma knife radiosurgery for cerebral arteriovenous malformationsAn autopsy report focusing on irradiation-induced changes observed in nidus-unrelated arteries

    Surg Neurol

    (1995)
  • L.A. Nedzi et al.

    Variables associated with the development of complications from radiosurgery of intracranial tumors

    Int J Radiat Oncol Biol Phys

    (1991)
  • O. Waltimo

    The relationship of size, density and localization of intracranial arteriovenous malformations to the type of initial symptom

    J Neurol Sci

    (1973)
  • O.O. Betti et al.

    Stereotactic radiosurgery with the linear acceleratorTreatment of arteriovenous malformations

    Neurosurgery

    (1989)
  • F. Colombo et al.

    Linear accelerator radiosurgery of cerebral artenovenous malformations

    Neurosurgery

    (1989)
  • F. Colombo et al.

    Linear accelerator radiosurgery of cerebral arteriovenous malformationsAn update

    Neurosurgery

    (1994)
  • W.A. Friedman et al.

    Linear accelerator radiosurgery for arteriovenous malformations

    J Neurosurg

    (1992)
  • W.A. Friedman et al.

    Linear accelerator radiosurgery for arteriovenous malformationsThe relationship of size to outcome

    J Neurosurg

    (1995)
  • B. Karlsson et al.

    Prediction of obliteration after gamma knife surgery for cerebral arteriovenous malformations

    Neurosurgery

    (1997)
  • J.S. Loeffler et al.

    Stereotactic radiosurgery of the brain using a standard linear acceleratora study of early and late effects

    Radiother Oncol

    (1990)
  • L.B. Marks et al.

    The influence of volume on the tolerance of the brain to radiosurgery [published erratum appears in J Neurosurg 1992;76(2):343]

    J Neurosurg

    (1991)
  • M.R. McKenzie et al.

    Early and late complications following dynamic stereotactic radiosurgery and fractionated stereotactic radiotherapy

    Can J Neurol Sci

    (1993)
  • L. Souhami et al.

    Dynamic stereotactic radiosurgery in arteriovenous malformation. Preliminary treatment results

    Cancer

    (1990)
  • O.K. Steinberg et al.

    Stereotactic heavy-charged-particle Bragg-peak radiation for intracranial arteriovenous malformations

    N Engl J Med

    (1990)
  • Yamamoto Y, Coffey RJ, Nichols DA, Shaw EG. Interim report on the radiosurgical treatment of cerebral arteriovenous...
  • M. Yamamoto et al.

    Gamma knife radiosurgery for arteriovenous malformationsLong-term follow-up results focusing on complications occurring more than 5 years after irradiation

    Neurosurgery

    (1996)
  • Y.P. Gobin et al.

    Treatment of brain arteriovenous malformations by embolization and radiosurgery

    J Neurosurg

    (1996)
  • J.A. Mathis et al.

    The efficacy of particulate embolization combined with stereotactic radiosurgery for treatment of large arteriovenous malformations of the brain

    Am J Neuroradiol

    (1995)
  • V. Seifert et al.

    Clinical and radiological evaluation of long-term results of stereotactic proton beam radiosurgery in patients with cerebral arteriovenous malformations

    J Neurosurg

    (1994)
  • B.E. Pollock et al.

    Repeat stereotactic radiosurgery of arteriovenous malformationsFactors associated with incomplete obliteration

    Neurosurgery

    (1996)
  • G.K. Steinberg et al.

    Surgical resection of large incompletely treated intracranial arteriovenous malformations following stereotactic radiosurgery

    J Neurosurg

    (1996)
  • R.F. Spetzler et al.

    A proposed grading system for arteriovenous malformations

    J Neurosurg

    (1986)
  • G.C. Dooms et al.

    Brain radiation lesions. MR imaging

    Radiology

    (1986)
  • L. Kihlstrom et al.

    Magnetic resonance imaging of obliterated arteriovenous malformations up to 23 years after radiosurgery

    J Neurosurg

    (1997)
  • J.V. Tranchida et al.

    Imaging of arteriovenous malformation following stereotactic radiosurgery

    Pediatr Radiol

    (1997)
  • Cited by (0)

    View full text