Factors associated with endocrine deficits after stereotactic radiosurgery of pituitary adenomas.
OBJECTIVE
To analyze the factors associated with anterior pituitary deficits after pituitary adenoma stereotactic radiosurgery (SRS).


METHODS
The tumor, pituitary stalk, and pituitary gland were segmented on the dose plans of 82 patients (secreting tumors, n = 53; nonsecreting tumors, n=29) for dose-volume analysis. No patient had undergone prior radiation therapy and all patients had at least 12 months of endocrinological follow-up (median, 63 months; mean, 69 months; range, 13-134).


RESULTS
Thirty-four patients (41%) developed new anterior pituitary deficits at a median of 32 months (range, 2-118) after SRS. The risk of developing new anterior pituitary deficits was 16% and 45% at 2 and 5 years, respectively. Multivariate analysis of the entire group showed that poor visualization of the pituitary gland (hazard ratio [HR]=2.63, 95% confidence interval [CI]=1.10-6.25, P=.03) was associated with a higher rate of new anterior pituitary deficits. Dosimetric analysis of 60 patients whose pituitary gland could be clearly identified showed that increasing mean pituitary gland radiation dose correlated with new anterior pituitary deficits (HR=1.11, 95% CI=1.02-1.20, P=.02). New anterior pituitary deficits stratified by mean pituitary gland radiation dose: <or=7.5 Gy, 0% (0/7); 7.6 to 13.2 Gy, 29% (7/24); 13.3 to 19.1 Gy, 39% (9/23); >19.1 Gy, 83% (5/6).


CONCLUSIONS
New endocrine deficits after pituitary adenoma radiosurgery were correlated with increasing radiation dose to the pituitary gland. Methods that limit the radiation dose to the pituitary gland during SRS may increase the probability of preserving pituitary function.
Leenstra
James L
JL
Department of Radiation Oncology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
Tanaka
Shota
S
Kline
Robert W
RW
Brown
Paul D
PD
Link
Michael J
MJ
Nippoldt
Todd B
TB
Young
William F
WF
Pollock
Bruce E
BE
D000236:Adenoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007018:Hypopituitarism / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D010903:Pituitary Gland, Anterior / Q000503:physiopathology / Q000528:radiation effects* / Q000601:surgery*; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D011446:Prospective Studies; D011859:Radiography; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors