Stereotactic radiosurgery for chordoma: a report from the North American Gamma Knife Consortium.
BACKGROUND
Although considered slow-growing, low-grade malignancies, chordomas are locally aggressive and destructive tumors with high recurrence rates.


OBJECTIVE
To assess patient survival, tumor control, complications, and selected variables that predict outcome in patients who underwent Gamma Knife stereotactic radiosurgery (SRS) as primary, adjuvant, or salvage management for chordomas of the skull base.


METHODS
Six participating centers of the North American Gamma Knife Consortium identified 71 patients who underwent SRS for chordoma. The median patient age was 45 years (range, 7-80 years). The median SRS target volume was 7.1 cm³ (range, 0.9-109 cm³), and median margin dose was 15.0 Gy (range, 9-25 Gy).


RESULTS
At a median follow-up of 5 years (range, 0.6-14 years) after SRS, 23 patients died of tumor progression. The 5-year actuarial overall survival after SRS was 80% for the entire group, 93% for the no prior fractionated radiation therapy (RT) group (n = 50), and 43% for the prior RT group (n = 21). Younger age, longer interval between initial diagnosis and SRS, no prior RT, < 2 cranial nerve deficits, and smaller total tumor volume were significantly associated with longer patient survival. The 5-year treated tumor control rate after SRS was 66% for the entire group, 69% for the no prior RT group, and 62% for the prior RT group. Older age, recurrent group, prior RT, and larger tumor volume were significantly associated with worse tumor control.


CONCLUSIONS
Stereotactic radiosurgery is a potent treatment option for small sized chordomas, especially in younger patients and as part of a multipronged attack that includes surgical resection when possible.
Department of Neurological Surgery, and Radiation Oncology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
Hideyuki
H
Kano
Fawaad O
FO
Iqbal
Jason
J
Sheehan
David
D
Mathieu
Zachary A
ZA
Seymour
Ajay
A
Niranjan
John C
JC
Flickinger
Douglas
D
Kondziolka
Bruce E
BE
Pollock
Gail
G
Rosseau
Penny K
PK
Sneed
Michael W
MW
McDermott
L Dade
LD
Lunsford
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000401:mortality / Q000601:surgery*; D002648:Child; D002817:Chordoma / Q000401:mortality / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery; D055815:Young Adult