Gamma knife radiosurgery for pituitary tumors: A systematic review and meta‐analysis

To describe and evaluate outcomes of Gamma Knife radiosurgery (GK) for the treatment of pituitary tumors over the past twenty years, a systematic review and meta‐analysis according to PRISMA statement was performed. Articles counting more than 30 patients were included. A weighted random effects models was used to calculate pooled outcome estimates. From 459 abstract reviews, 52 retrospective studies were included. Among them, 18 reported on non‐functioning pituitary adenomas (NFPA), 13 on growth hormone (GH)‐secreting adenomas, six on adrenocortico-tropic hormone (ACTH)‐secreting adenomas, four on prolactin hormone (PRL)‐secreting adeno-mas, and 11 on craniopharyngiomas. Overall tumor control and five‐year progression free survival (PFS) estimate after one GK procedure for NFPA was 93% (95% CI 89–97%) and 95% (95% CI 91– 99%), respectively. In case of secreting pituitary adenomas, overall remission (cure without need for medication) estimates were 45% (95% CI 35–54%) for GH‐secreting adenomas, 64% (95% CI 0.52– 0.75%) for ACTH‐secreting adenomas and 34% (95% CI: 19–48%) for PRL‐secreting adenomas. The pooled analysis for overall tumor control and five‐year PFS estimate after GK for craniopharyngi-oma was 74% (95% CI 67–81%) and 70% (95% CI: 64–76%), respectively. This meta‐analysis confirms and quantifies safety and effectiveness of GK for pituitary tumors.