Proton beam stereotactic radiosurgery for pediatric cerebral arteriovenous malformations.
BACKGROUND
For cerebral arteriovenous malformations (AVMs) determined to be high risk for surgery or endovascular embolization, stereotactic radiosurgery (SRS) is considered the mainstay of treatment.


OBJECTIVE
To determine the outcomes of pediatric patients with AVMs treated with proton SRS.


METHODS
We reviewed the records of 44 consecutively treated pediatric patients (younger than 18 years of age) who underwent proton SRS at our institution from 1998 to 2010. The median target volume was 4.5 ± 5.9 mL (range, 0.3-29.0 mL) and the median maximal diameter was 3.6 ± 1.5 cm (range, 1-6 cm). Radiation was administered with a median prescription dose of 15.50 ± 1.87 CGE to the 90% isodose.


RESULTS
At a median follow-up of 52 ± 25 months, 2 patients (4.5%) had no response, 24 patients (59.1%) had a partial response, and 18 patients (40.9%) experienced obliteration of their AVM. The median time to obliteration was 49 ± 26 months, including 17 patients who underwent repeat proton radiosurgery. Four patients (9%) experienced hemorrhage after treatment at a median time of 45 ± 15 months. Univariate analysis identified modified AVM scale score (P = .045), single fraction treatment (0.04), larger prescription dose (0.01), larger maximum dose (<0.001), and larger minimum dose (0.01) to be associated with AVM obliteration.


CONCLUSIONS
High-risk AVMs can be safely treated with proton radiosurgery in the pediatric population. Because protons deposit energy more selectively than photons, there is the potential benefit of protons to lower the probability of damage to healthy tissue in the developing brain.
Departments of *Neurosurgery and ‡Radiation Oncology, §Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; ¶Department of Radiation Oncology, University of California San Diego, San Diego, California; ‖Department of Neurosurgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.
Brian P
BP
Walcott
Jona A
JA
Hattangadi-Gluth
Christopher J
CJ
Stapleton
Christopher S
CS
Ogilvy
Paul H
PH
Chapman
Jay S
JS
Loeffler
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000532:radiotherapy*; D008297:Male; D061766:Proton Therapy / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome