Gamma Knife radiosurgery as the initial treatment for elderly patients with nonfunctioning pituitary adenomas

The aim of this study was to investigate the efficacy and safety of initial Gamma Knife radiosurgery (GKRS) for elderly patients with nonfunctioning pituitary adenomas (NFPAs).

We retrospectively reviewed 45 elderly patients underwent GKRS as the initial treatment for NFPAs at our institution between December 2007 and December 2017. Patients' radiographic and clinical data were collected.

The median age of patients at the time of GKRS was 71 years (range 65-82 years). The median tumor volume was 2.6 cm³ (range 0.3-21.8 cm³). The median marginal dose was 13 Gy (range 6-23 Gy). The median maximum dose to the optic apparatus was 6.5 Gy (range 2.3-10.3 Gy). Thirty-five patients (77.8%) achieved tumor regression, 6 patients (13.3%) had tumor stable and 4 patients (8.9%) occurred tumor progression during a median radiological follow-up time of 51.4 months (range 11.1-158.7 months). The crude tumor control rate was 91.1%. The actuarial tumor control rates were 100%, 95.0%, 87.6%, and 87.6%, at 1, 3, 5, and 10 years after initial GKRS, respectively. New-onset hypopituitarism occurred in 6 patients. Two patients with pre-GKRS visual dysfunction developed further deterioration of visual function. No other radiation-induced complications were noted.

Initial GKRS can provide a high tumor control rate as well as low risk of postradiosurgical complications for elderly patients with NFPAs. Attention should be paid to avoid radiation-related adverse effects including hypopituitarism, optic neuropathy and cranial neuropathy in elderly patients.