Frailty in Patients Undergoing Surgery for Brain Tumors: A Systematic Review of the Literature

IntroductionEmerging literature suggests that frailty may be an important driver of postoperative outcomes in patients undergoing surgery for brain tumors. We systematically reviewed the literature on frailty in brain tumor patients with respect to three questions: What methods of frailty assessment have been applied to brain tumor patients? What thresholds have been defined to distinguish between different levels of frailty? What clinical outcomes does frailty predict in brain tumor patients? MethodsA literature search was conducted using PubMed, Embase, The Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov. Included studies were specific to brain tumor patients, used a validated instrument to assess frailty, and measured the impact of frailty upon postoperative outcomes. ResultsOf 753 citations, 21 studies met our inclusion criteria. Frailty instruments studied, in order of frequency reported, included the 5-factor modified frailty index, 11-factor modified frailty index, Johns Hopkins Adjusted Clinical Groups frailty-defining diagnosis indicator, and Hopkins Frailty Score. Multiple different conventions and thresholds for distinguishing levels of frailty were reported. Clinical outcomes associated with frailty included mortality, survival, complications, length of stay (LOS), charges, costs, discharge disposition, readmissions, and operative time. ConclusionsFrailty is an increasingly popular concept in brain tumor patients that is associated with important clinical outcomes. However, the extant literature is largelycomprised of retrospective studies with heterogeneous definitions of frailty, thresholds for defining levels of frailty, and patient populations. Further work is needed to understand best practices in assessing frailty inbrain tumor patients and applying these concepts to clinical practice.