Frailty and postoperative outcomes in brain tumor patients: a systematic review subdivided by tumor etiology. - Qureshi HM; Tabor JK; Pickens K; Lei H; Vasandani S; Jalal MI; Vetsa S; Elsamadicy A; Marianayagam N; Theriault BC; Fulbright RK; Qin R; et al. (Journal of neuro-oncology, 2023)