Long-Term Outcomes of Single-Session Stereotactic Radiosurgery for Cerebellar Arteriovenous Malformation, with a Median Follow-Up of 10 Years.
OBJECTIVE
Cerebellar arteriovenous malformation (C-AVM) is poorly tolerated because of its aggressive natural history. The aim of this study was to delineate long-term outcomes of Gamma Knife stereotactic radiosurgery (GKRS) for C-AVM.


METHODS
The outcomes of 45 patients who underwent GKRS for C-AVMs at our institution were retrospectively analyzed. Event-free survival was defined as free from any neurologic deficits caused by AVMs or adverse phenomena from the treatment.


RESULTS
The median age and follow-up were 41 years (range, 6-77 years) and 120 months (range, 5-291 months), respectively. The median volume and Pollock-Flickinger radiosurgical AVM score were 1.3 cm3(range, 0.1-8.3 cm3) and 1.26 (range, 0.5-2.06), respectively. Actuarial obliteration rates were 46%, 75%, and 90% at 3, 5, and 6 years, respectively. Multivariate analysis showed that the maximal diameter ≤15 mm (P = 0.021) and margin dose >20 Gy (P = 0.0008) were significantly associated with better obliteration. Four patients experienced posttreatment hemorrhages, and annual hemorrhage rates were 1.9% and 0.30% before and after obliteration, respectively. One patient died because of hemorrhage, whereas the other 3 patients spontaneously recovered. Perifocal edema was confirmed in 8 (16%); however, no symptomatic edema was observed. Overall, neurologic deteriorations were noted in 4 patients; 3 were because of posttreatment hemorrhage, and 1 was because of pretreatment angiography. The event-free survival rates were 96%, 93%, and 93% at 4, 10, and 15 years, respectively.


CONCLUSIONS
GKRS is a reasonable intervention for C-AVMs. Symptomatic complications are rare, and the long-term outcomes are favorable.
Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan. Electronic address: hirohasegawa-tky@umin.ac.jp.
Hirotaka
H
Hasegawa
Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan.
Shunya
S
Hanakita
Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan.
Masahiro
M
Shin
Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan.
Masaaki
M
Shojima
Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan.
Tomoyuki
T
Koga
Department of Radiation Oncology, The University of Tokyo Hospital, Tokyo, Japan.
Wataru
W
Takahashi
Department of Radiation Oncology, The University of Tokyo Hospital, Tokyo, Japan.
Madoka
M
Sakuramachi
Department of Radiation Oncology, The University of Tokyo Hospital, Tokyo, Japan.
Akihiro K
AK
Nomoto
Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan.
Nobuhito
N
Saito
D000293:Adolescent; D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction / Q000639:trends; D001164:Arteriovenous Fistula / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D002531:Cerebellum / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000639:trends*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
Arteriovenous malformation; Cerebellum; Gamma Knife; Intracranial hemorrhage; Posterior fossa; Stereotactic radiosurgery