Effects of gamma knife radiosurgery of pituitary adenomas on pituitary function.
OBJECTIVE
The authors undertook a retrospective analysis of the incidence and time course of pituitary insufficiency following gamma knife radiosurgery (GKS) for pituitary adenomas.


METHODS
Pituitary adenomas in 92 patients were analyzed. There were 61 hormonally inactive tumors, 18 prolactinomas, and nine somatotropic and four adrenocorticotropic adenomas. The mean tumor volume was 3.8 cm3 (range 0.2-14.6 cm3). The mean prescription dose was 15 Gy. The mean prescription isodose was 50.7%. The mean follow-up time was 4.6 years (range 1.2-10 years). The following new or deteriorating insufficiencies that did not require treatment were recorded for the different pituitary axes: follicle-stimulating hormone (FSH)/ luteinizing hormone (LH) 19 (20.6%), thyroid-stimulating hormone (TSH) 32 (34.8%), adrenocorticotropic hormone (ACTH) 10 (10.9%), and growth hormone (GH) 26 (28.3%). For new insufficiencies or deterioration requiring replacement therapy, the figures were as follows: FSH/LH 20 (21.7%), TSH 22 (23.9%), ACTH eight (8.7%), and GH 12 (13%). Spot dosimetry was performed in 59 patients in the hypothalamic region, the pituitary gland, and pituitary stalk. The pituitary stalks in patients with deterioration of pituitary function received a statistically higher dosage of radiation, 7.7 +/- 3.7 Gy compared with 5.5 +/- 3 Gy (p = 0.03).


CONCLUSIONS
The function of the residual normal pituitary gland is less affected following GKS of pituitary adenomas than after fractionated radiotherapy. Nonetheless, increased attention needs to be exercised to reduce the dose to the stalk and pituitary gland to minimize the incidence of these complications.
Feigl
Gunther Christian
GC
International Neuroscience Institute, Hannover, Germany.
Bonelli
Christine Maria
CM
Berghold
Andrea
A
Mokry
Michael
M
D000236:Adenoma / Q000453:epidemiology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007018:Hypopituitarism / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000503:physiopathology*; D010911:Pituitary Neoplasms / Q000453:epidemiology / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D016634:Radiosurgery / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors