Phase angle as a prognostic factor in patients with cancer: a systematic review of the existing evidence via a meta-analysis.

Background: the phase angle (PA) is expressed via bioelectrical impedance and an indicator of cell membrane health, integrity, hydration, and nutritional status. The associations between PA and cancer survival are inconsistent and unclear. This study aimed to assess PA's role as a prognostic marker of cancer survival. Methods: we searched PubMed and EMBASE to identify all relevant studies up to December 2023. A meta-analysis was performed to clarify PA's prognostic role for cancer patients. Results: a total of 30 studies covering 6587 participants were included in this study. There was a significant prognostic role for PA in the context of cancer patients' survival (HR = 0.73; 95 % CI, 0.66-0.81, p < 0.0001, I2 = 0.0 %). Patients with low PA values were 27 % less likely to survive than patients with high values. Our subgroup analyses showed that geographical population (American: HR = 0.66, 95 % CI: 0.55-0.79, I2 = 0.0 %; European: HR = 0.63, 95 % CI: 0.47-0.84, I2 = 23.2 %; Asian: HR = 0.48, 95 % CI: 0.31-0.74), the type of cancer (head and neck, colorectal, lung, or pancreatic cancer), and type of therapy (palliative vs. non-palliative treatment) did not change the prognostic value. Conclusions: the findings highlight the potential of PA to be a non-invasive, cost-effective prognostic tool in oncological care.