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 adrenocorticotropic hormone (ACTH)-secreting adenomas, four on prolactin hormone (PRL)-secreting adenomas, 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 craniopharyngioma 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.