Radiation-Induced Changes Associated with Obliteration of Brain AVMs after Repeat Radiosurgery

Area of Science:

• Neurosurgery
• Radiation Oncology
• Radiology

Background:

• Stereotactic radiosurgery for brain arteriovenous malformations (AVMs) can lead to radiation-induced changes.
• These changes may cause symptomatic complications, necessitating further evaluation.

Purpose of the Study:

• To evaluate the incidence of radiation-induced changes after initial gamma knife radiosurgery for brain AVMs.
• To assess the efficacy of repeat gamma knife radiosurgery for AVMs that remain incompletely obliterated.

Main Methods:

• Retrospective review of 150 patients treated with gamma knife radiosurgery for AVMs (2002-2020).
• Analysis of 25 patients who underwent repeat radiosurgery for incomplete AVM obliteration.
• Recording of radiation-induced changes and obliteration rates after initial and repeat treatments.

Main Results:

• Radiologic radiation-induced changes occurred in 32% of patients after the first treatment; 8% had symptomatic changes.
• Repeat gamma knife radiosurgery achieved complete AVM obliteration in 64% of patients.
• Radiation-induced changes after the first treatment were significantly associated with successful obliteration by repeat radiosurgery (OR = 24.0, P = .007).

Conclusions:

• Radiation-induced changes after initial radiosurgery are associated with successful AVM obliteration following repeat treatment.
• Repeat gamma knife radiosurgery offers a favorable outcome for incompletely obliterated AVMs, even with prior radiation-induced changes.
• The risk of symptomatic radiation-induced changes did not increase with retreatment.