Intra- and Inter-Rater Reliability of Bioimpedance in the Evaluation of Lymphedema Secondary to Treatment of Breast Cancer.

The objective of the study was to evaluate the intra- and inter-rater reliability of bioimpedance in determining upper limb volume in women with lymphedema resulting from breast cancer treatment, as well as its correlation with the upper limb volume calculated by circumferential measurement. A blind cross-sectional study was performed in which 27 women (62.59 ± 10.50 years) were evaluated with upper limb lymphedema secondary to breast cancer treatment. Two examiners performed assessments in the same volunteers independently and twice, with an interval of 1 week between assessments. The collections were performed by the direct tetrapolar multifrequency segmental bioimpedance and by the circumference of the upper limb homolateral to the breast cancer. The results of the circumference showed that the homolateral limb had lymphedema. The intra- and inter-rater analysis showed excellent reliability with intraclass correlation coefficient (ICC) values ranging from 0.954 to 0.999 for the amount of liquid and excellent reliability with ICC values ranging from 0.852 to 0.999 for the electrical impedance of the upper limb with lymphedema. The correlation was strong and negative (p < 0.05) between intracellular, extracellular, and total water when associated with electrical impedance and moderate and positive (p < 0.05) when associated with upper limb volume for all frequencies. The correlations between upper limb volume and water quantities were moderate and positive (p < 0.05). The results indicate that bioimpedance is a reliable method for the evaluation of lymphedema, and the volume of the homolateral upper limb is associated with the amount of water in women with lymphedema secondary to the treatment of breast cancer.