The Prognostic Role of Phase Angle in Advanced Cancer Patients: A Systematic Review

Phase angle (PA) is a ratio between the reactance and resistance obtained by bioelectric impedance analysis and has been interpreted as a cell membrane integrity indicator and a predictor of total body cell mass. A low PA may suggest deterioration of the cell membrane, which in advanced cancer patients may result in a reduced overall survival (OS). This systematic review sought to investigate the current evidence regarding whether there is an association between PA and OS in patients with advanced cancer (ie, metastatic disease). The search was conducted on electronic databases in August 2017. A total of 34 articles were identified in the initial literature search. Nine studies reporting on 1496 patients were deemed eligible according to our inclusion criteria. PA data were analyzed as continuous variables or according to different cutoffs, under a frequency of 50 Khz. Low PA was associated with worse nutrition status evaluated by body mass index, serum albumin level, transferrin, and fat-free mass. The median OS of the included papers varied from 25.5-330 days, and all studies analyzed showed a significant association between PA and OS, in that patients with low PA had worse OS. Future studies are necessary to justify the use of PA in therapeutic decisions for this population and to evaluate whether nutrition status can influence the association between PA and survival.