Gamma knife radiosurgery for patients with nonfunctioning pituitary adenomas: results from a 15-year experience.
OBJECTIVE
To evaluate the efficacy and complications of stereotactic radiosurgery for patients with nonfunctioning pituitary adenomas (NFA).


METHODS
This was a retrospective review of 62 patients with NFA undergoing radiosurgery between 1992 and 2004, of whom 59 (95%) underwent prior tumor resection. The median treatment volume was 4.0 cm(3) (range, 0.8-12.9). The median treatment dose to the tumor margin was 16 Gy (range, 11-20). The median maximum point dose to the optic apparatus was 9.5 Gy (range, 5.0-12.6). The median follow-up period after radiosurgery was 64 months (range, 23-161).


RESULTS
Tumor size decreased for 37 patients (60%) and remained unchanged for 23 patients (37%). Two patients (3%) had tumor growth outside the prescribed treatment volume and required additional treatment (fractionated radiation therapy, n = 1; repeat radiosurgery, n = 1). Tumor growth control was 95% at 3 and 7 years after radiosurgery. Eleven (27%) of 41 patients with normal (n = 30) or partial (n = 11) anterior pituitary function before radiosurgery developed new deficits at a median of 24 months after radiosurgery. The risk of developing new anterior pituitary deficits at 5 years was 32%. The 5-year risk of developing new anterior pituitary deficits was 18% for patients with a tumor volume of < or = 4.0 cm(3) compared with 58% for patients with a tumor volume >4.0 cm(3) (risk ratio = 4.5; 95% confidence interval = 1.3-14.9, p = 0.02). No patient had a decline in visual function.


CONCLUSIONS
Stereotactic radiosurgery is effective in the management of patients with residual or recurrent NFA, although longer follow-up is needed to evaluate long-term outcomes. The primary complication is hypopituitarism, and the risk of developing new anterior pituitary deficits correlates with the size of the irradiated tumor.
Pollock
Bruce E
BE
Department of Neurological Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. pollock.bruce@mayo.edu
Cochran
Joseph
J
Natt
Neena
N
Brown
Paul D
PD
Erickson
Dana
D
Link
Michael J
MJ
Garces
Yolanda I
YI
Foote
Robert L
RL
Stafford
Scott L
SL
Schomberg
Paula J
PJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007018:Hypopituitarism / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D047368:Tumor Burden