Bioelectrical Phase Angle in Patients with Breast Cancer: A Systematic Review

Abstract

Breast cancer (BC) is the most common cancer diagnosed among women worldwide. Phase angle (PhA), a proxy measure of membrane integrity and function, has gained relevance in clinical practice and it has been suggested to be a prognostic and nutritional indicator. This systematic review aimed to explore PhA and its relationship with nutritional status and survival in BC patients. Four databases (PubMed, EMBASE, Web of Science, and CINAHL) were systematically searched until September 2021 for studies evaluating PhA in BC patients. A total of 16 studies met the inclusion criteria, where 11 were observational studies and 5 were interventional studies. Baseline PhA-value varied from 4.9 to 6.30 degrees, showing a great variability and heterogeneity across the selected studies. Available data suggested that PhA decreased by 5-15% after completing chemotherapy, and those effects might persist in the long term. However, the use of tailored nutritional and/or exercise programs during and after therapy could prevent PhA reduction and body derangement. High PhA values were found in women displaying a better nutritional status, while inconsistent data were found on survival. Therefore, further studies are needed to focus on the clinical relevance of PhA in BC patients, evaluating its association with disease outcomes and survival.

Keywords: bioimpedance-analysis; chemotherapy; fat mass; muscle strength; survival.

Figure 1

Flow diagram of the literature search process.

Figure 2

Baseline PhA values in patients with BC.

Figure 3

White arrows indicate that PhA is negatively affected by cancer therapy (−) and positively by lifestyle intervention (+). Black arrows indicate that PhA serves as a predictor of nutritional and functional status (+) in women with BC, while data are inconsistent about survival (?).