Stereotactic Radiosurgery Provides Long-Term Safety for Patients With Arteriovenous Malformations in the Diencephalon and Brainstem: The Optimal Dose Selection and Long-Term Outcomes

Abstract

BACKGROUND: Arteriovenous malformations (AVMs) of the diencephalon (DC) and brainstem (BS) are difficult to treat. Stereotactic radiosurgery (SRS) is a reasonable option; however, an optimal radiosurgical dose needs to be established to optimize long-term outcomes. OBJECTIVE: To evaluate dose-dependent long-term outcomes of SRS for DC/BS-AVMs. METHODS: We retrospectively analyzed the long-term outcomes of 118 patients who had SRS-treated DC/BS-AVMs. The outcomes included post-SRS hemorrhage, AVM obliteration, neurological outcomes, and disease-specific survival. According to margin doses, the patients were classified into low (<18 Gy), medium (18-20 Gy), and high (>20 Gy) dose groups. RESULTS: SRS reduced the annual hemorrhage rate from 8.6% to 1.6% before obliteration and 0.0% after obliteration. The cumulative hemorrhage rate in the low dose group was likely to be higher than that in the other groups (P = .113). The cumulative obliteration rates in the entire cohort were 74% and 83% at 5 and 10 years, respectively, and were significantly lower in the low dose group than in the other groups (vs medium dose: P = .027, vs high dose: P = .016). Multivariate analyses demonstrated that low dose SRS was significantly associated with worse obliteration rates (hazard ratio 0.18, 95% CI 0.04-0.79; P = .023). CONCLUSION: SRS with a margin dose of 18 to 20 Gy for DC/BS-AVMs may be optimal, providing a higher obliteration rate and lower risk of post-SRS hemorrhage than lower dose SRS. Dose reduction to <18 Gy should only be optional when higher doses are intolerable.

In Reply: Stereotactic Radiosurgery Provides Long-Term Safety for Patients With Arteriovenous Malformations in the Diencephalon and Brainstem: The Optimal Dose Selection and Long-Term Outcomes

“…We sincerely appreciate the opportunity to respond to the Letter to the Editor from Dr Wang 1 on our recent article titled “Stereotactic radiosurgery provides long-term safety for patients with arteriovenous malformations in the diencephalon and brainstem: the optimal dose selection and long-term outcomes.” 2 We respectfully acknowledge Dr Wang for his thoughtful and encouraging comments on our study.…”

Effect of Cobalt-60 Treatment Dose Rate on Arteriovenous Malformation Obliteration After Stereotactic Radiosurgery With Gamma Knife

“…2,[5][6][7][8][9][10][11] Higher SRS dose and biologically effective dose (BED) are associated with increased AVM obliteration. 6,7,[9][10][11][12][13][14][15][16][17][18] However, there is limited evidence regarding the effect of cobalt-60 treatment dose rate on SRS treatment efficacy and associated toxicity. Although BED is dependent on many factors including total treatment time, lesion size, and marginal prescription dose, SRS dose rate is an unbiased variable that is only dependent on the age of the cobalt-60 sources in the gamma knife (GK) machine.…”

Letter: Stereotactic Radiosurgery Provides Long-Term Safety for Patients With Arteriovenous Malformations in the Diencephalon and Brainstem: The Optimal Dose Selection and Long-Term Outcomes

“…I read with great interest the article by Shinya et al 1 titled “Stereotactic Radiosurgery Provides Long-Term Safety for Patients With Arteriovenous Malformations in the Diencephalon and Brainstem: The Optimal Dose Selection and Long-Term Outcomes.” The authors retrospectively analyzed the long-term outcomes of 118 patients with arteriovenous malformations (AVMs) in the diencephalon (DC) and brainstem (BS) treated with different grades of radiosurgical dose in stereotactic radiosurgery (SRS). These patients were divided into low-dose (<18 Gy), medium-dose (18-20 Gy), and high-dose (>20 Gy) groups based on the margin dose.…”