Background
Systematic review and meta-analysis. 35 studies, 1,621 patients, SRS (Gamma Knife or LINAC) for pituitary adenomas (nonfunctioning, acromegaly, Cushing's, prolactinoma, TSH-secreting).
Interventions and follow up
Treatment: SRS (Gamma Knife or LINAC) for nonfunctioning and functioning pituitary adenomas
Primary endpoint: Tumor growth control; hormone normalization (functioning); complications
mFollow up: Varied by study (minimum 2 yr per study)
Primary endpoint: Tumor growth control; hormone normalization (functioning); complications
mFollow up: Varied by study (minimum 2 yr per study)
Results
Tumor control rate: ~90% across all adenoma types
Hormone normalization (acromegaly): ~50–60% by strict criteria
Hormone normalization (Cushing's): ~55–76%
New hypopituitarism after SRS: ~20–30% (lower than fractionated RT)
Hormone normalization (acromegaly): ~50–60% by strict criteria
Hormone normalization (Cushing's): ~55–76%
New hypopituitarism after SRS: ~20–30% (lower than fractionated RT)
Adverse events
New hypopituitarism: ~20–30% (lower than fractionated RT)
Radiation-induced neoplasia: Very rare (<0.1% at 5–10 yr)
Cerebral vasculopathy: Rare, lower than fractionated RT
Visual deterioration: <3% when optic apparatus <8–10 Gy
Deaths: None in modern series
Radiation-induced neoplasia: Very rare (<0.1% at 5–10 yr)
Cerebral vasculopathy: Rare, lower than fractionated RT
Visual deterioration: <3% when optic apparatus <8–10 Gy
Deaths: None in modern series
Conclusions
SRS achieves ~90% tumor control across pituitary adenoma types with acceptable toxicity. Risks of hypopituitarism, neoplasia, and vasculopathy appear lower than fractionated RT. Hormone normalization rates vary widely due to inconsistent endocrinologic criteria.
Key Limitations
Pooled retrospective series; heterogeneous remission/normalization criteria; variable dose and follow-up; publication bias; limited long-term endocrine surveillance.
Clinical Context
Supports SRS as adjuvant/salvage for residual or recurrent pituitary adenoma after transsphenoidal surgery, with favorable late-toxicity profile vs conventional fractionated RT.