A cost comparative study of gamma knife radiosurgery versus open surgery for intracranial pathology.

J Clin Neurosci. 2015;22(1):184–8.
Caruso JP, Moosa S, Fezeu F, Ramesh A, Sheehan JP.

Stereotactic radiosurgery is increasingly used to treat multiple (four or more) brain metastases. Preserving cognitive functions is a highly relevant treatment goal because cognitive deteriorations may negatively affect a patient’s quality of life. The aim of this study was to assess cognitive change, at the group and individual level, in patients with 1 to 10 brain metastases up to 9 months after Gamma Knife radiosurgery (GKRS).

Materials and methods
Ninety-two patients with 1 to 10 newly diagnosed brain metastases, expected survival >3 months and Karnofsky Performance Status (KPS) ≥70 and 104 non-cancer controls were included. A neuropsychological test battery was administered before GKRS (n = 92) and at 3 (n = 66), 6 (n = 52) and 9 (n = 41) months after GKRS. The course of test performances, while taking into account practice effects, was analysed using linear mixed models. Pre-GKRS predictors of cognitive trajectories were analysed. To determine proportions of individuals with cognitive changes, reliable change indices, with correction for practice effects, were calculated.

At the group level, immediate memory, working memory and information processing speed significantly improved over 9 months after GKRS. There were no cognitive declines. Neither number nor volume of brain metastases influenced cognitive change over time. At the individual level, proportions of patients with stable, improved or declined performances were comparable with controls, except for information processing speed (more individuals with improvements in patients) and motor dexterity (more improvements and declines in patients).

Cognitive functioning in patients with 1 to 10 brain metastases was preserved, or improved, up to 9 months
after GKRS. Neither number nor volume of brain metastases influenced cognitive performance.