Gamma knife radiosurgery in pituitary adenomas. A single-center experience

Stereotactic radiosurgery with gamma knife (GKS) is a treatment option for persistent or recurrent pituitary adenoma. The aim of our study was to report Argentine experience in GKS, assessing the efficacy and safety in our patients with pituitary adenomas. We performed a retrospective analysis of patients with pituitary adenomas treated with GKS between 2002 and 2017 in a single institution. Patient characteristics, biochemical remission rate (for functioning tumors), tumor control rate and adverse effects with GKS were investigated. The study cohort comprised 99 patients with a mean follow-up of 63 months: 51 somatotropinomas, 28 non-functioning adenomas, 15 corticotropinomas, 2 prolactinomas and 3 mixed pituitary tumors. The mean radiation dose was 30.6Gy for corticotropinomas, 29.3Gy for somatotropinomas and 19.6Gy for non-secreting adenomas. Global tumor control rate was 94.2%. Biochemical remission rate was 55.9%, being higher in acromegaly than in Cushing's disease (OR4.7, 95%Ci 2.1-10.4, p <0.0001). The mean time to remission was 29.5 months (range: 6-156). Hypopituitarism occurred in 26% of patients and those with Cushing's disease were more prone to develop new hormone deficiency after GKS (OR 2.93, 95%Ci 1.2-7.2, p = 0.019). This study shows argentine experience with the use of GKS in patients with pituitary adenomas, with similar results to those reported by centers with large radiosurgical experience. We achieved biochemical remission in more than 50% of patients and global tumor control in most of them. Hypopituitarism was the most frequent adverse effect, while others were infrequent.