Gamma knife stereotactic radiosurgery for acromegaly.
BACKGROUND
Gamma knife radiosurgery (GKR) is an adjuvant treatment for acromegaly if surgery fails to normalize GH hypersecretion.


OBJECTIVE
To examine the effect of GKR on tumor growth and hypersecretion, and to characterize the adverse effect of this treatment.


METHODS
Cross-sectional follow-up study. First, retrospective data pre- and post-GKR were collected. PATIENTS then underwent a predefined survey including radiological, endocrinological, ophthalmological, and neurosurgical evaluation.


METHODS
Norwegian National Center for gamma knife treatment.


METHODS
Sixty-one patients treated with GKR for acromegaly. Out of 55, 53 living patients underwent a detailed survey. The mean follow-up was 5.5 years. No patient was lost to follow-up.


RESULTS
Tumor growth was stopped in all patients. At 3, 5, and 10 years after GKR, 45, 58, and 86% of patients had normal IGF-I levels. Consecutive hormone value analysis showed that patients receiving GH-suppressive medication had a more rapid decline in hypersecretion than those who did not receive such medication. Evaluated by survey baseline values alone, non-elevated IGF-I and GH levels below 5 mIU/l were found in 38%. GH-suppressive medication was terminated in 16 out of 40 patients following GKR. Nine out of 53 surveyed patients (17%) had normal IGF-I and GH nadir below 2.6 mIU/l at glucose tolerance tests, while not on hormone-suppressive medication. Two patients developed minor visual field defects. Eight patients started hormone substitution therapy during the follow-up period.


CONCLUSIONS
GKR is an effective adjuvant treatment for residual acromegaly, carrying few side effects.
Vik-Mo
Einar Osland
EO
Department of Neurosurgery, Haukeland University Hospital, Bergen, Norway. e.o.vik-mo@medisin.uio.no
Oksnes
Marianne
M
Pedersen
Paal-Henning
PH
Wentzel-Larsen
Tore
T
Rødahl
Eyvind
E
Thorsen
Frits
F
Schreiner
Thomas
T
Aanderud
Sylvi
S
Lund-Johansen
Morten
M
D000172:Acromegaly / Q000401:mortality / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007018:Hypopituitarism / Q000209:etiology / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D010911:Pituitary Neoplasms / Q000401:mortality / Q000601:surgery*; D011183:Postoperative Complications / Q000401:mortality*; D016634:Radiosurgery / Q000009:adverse effects* / Q000401:mortality; D012189:Retrospective Studies; D014786:Vision Disorders / Q000209:etiology / Q000401:mortality