Relationship between the Phase Angle and Volume of Tumours in Patients with Lung Cancer

BACKGROUND/AIMS: The phase angle (PA) obtained by bioelectrical impedance has been used as a predictor of nutritional status in cancer. This study aimed to verify the association between the PA and tumour volume in non-small cell lung cancer (NSCLC) patients. METHODS: Volumetric determination of the tumour mass was performed using a computerised image analysis system incorporated in helical tomography. Lesion segmentation was performed by a semi-automatic process using a region growth algorithm with voxel aggregation. The PA was measured by bioelectrical impedance. RESULTS: A total of 30 male patients with a mean age of 65.6 years were evaluated. The mean values observed for body mass index, PA and tumour volume were 22.5 ± 4.19, 5.66 ± 0.9° and 163.2 ± 207.5 ml, respectively. The tumour volumes were negatively correlated with the PA (r = -0.55; p < 0.001) and positively correlated with the ratio between the extracellular mass and the body cell mass (ECM/BCM) (r = 0.59; p < 0.001). In multivariate analysis, independent predictors for both PA and ECM/BCM were tumour volume and Karnofsky performance status score. CONCLUSIONS: In NSCLC, the PA is closely associated with tumour volume, which may be important in early nutritional intervention.