Gamma Knife surgery for the management of glomus tumors: a multicenter study.
OBJECTIVE
Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after radiosurgery in a large, multicenter patient population.


METHODS
Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of radiosurgery. The median dose to the tumor margin was 15 Gy. The median duration of follow-up was 50.5 months (range 5-220 months).


RESULTS
Overall tumor control was achieved in 93% of patients at last follow-up; actuarial tumor control was 88% at 5 years postradiosurgery. Absence of trigeminal nerve dysfunction at the time of radiosurgery (p = 0.001) and higher number of isocenters (p = 0.005) were statistically associated with tumor progression-free tumor survival. Patients demonstrating new or progressive cranial nerve deficits were also likely to demonstrate tumor progression (p = 0.002). Pulsatile tinnitus improved in 49% of patients who reported it at presentation. New or progressive cranial nerve deficits were noted in 15% of patients; improvement in preexisting cranial nerve deficits was observed in 11% of patients. No patient died as a result of tumor progression.


CONCLUSIONS
Gamma Knife surgery was a well-tolerated management strategy that provided a high rate of long-term glomus tumor control. Symptomatic tinnitus improved in almost one-half of the patients. Overall neurological status and cranial nerve function were preserved or improved in the vast majority of patients after radiosurgery.
Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia 22908, USA. jsheehan@virginia.edu
Jason P
JP
Sheehan
Shota
S
Tanaka
Michael J
MJ
Link
Bruce E
BE
Pollock
Douglas
D
Kondziolka
David
D
Mathieu
Christopher
C
Duma
A Byron
AB
Young
Anthony M
AM
Kaufmann
Heyoung
H
McBride
Peter A
PA
Weisskopf
Zhiyuan
Z
Xu
Hideyuki
H
Kano
Huai-che
HC
Yang
L Dade
LD
Lunsford
D000206:Actuarial Analysis; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003389:Cranial Nerve Diseases / Q000209:etiology / Q000401:mortality; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D005918:Glomus Tumor / Q000401:mortality / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000601:surgery; D011183:Postoperative Complications / Q000209:etiology* / Q000401:mortality; D016634:Radiosurgery; D019292:Skull Base Neoplasms / Q000601:surgery*; D014012:Tinnitus / Q000209:etiology; D016896:Treatment Outcome; D020433:Trigeminal Nerve Diseases / Q000209:etiology / Q000401:mortality; D055815:Young Adult