The correlation between bioimpedance and outcomes of lymphedema treatment in breast cancer patients

Abstract

Bioimpedance can be used for lymphedema assessment. As lower as the frequency is, current passes through mostly extracellular fluid, considered to be major part of changes during treatment of lymphedema. The aim of this study is to evaluate responsiveness to treatment and prognosis by using bioimpedance and to indentify that the lower frequency impedance more reflects the actual volume changes during treatment. Among the subjects who visited outpatient clinic from December, 2015 to December, 2016 and underwent initial complex decongestive therapy (CDT) for 2 weeks with bioimpedance analysis before and after treatment, we included 64 unilateral breast cancer related lymphedema (BCRL) patients. The ratios of single frequency bioimpedance analysis (SFBIA) at 5 kHz, 1 kHz and the ratio of bioimpedance at 0 kHz were measured. The volume of the affected arm was estimated by integrating arm circumference for 4 cm intervals. The higher ratios of impedance at 0 kHz, 1 kHz, and 5 kHz before CDT were statistically significantly correlated with arm volume reduction in affected arm. Furthermore, as the frequency of SFBIA increases in order of 0 kHz, 1 kHz, and 5 kHz, the coefficient of correlation ( r ) showed tendency to increase. However, in the analysis of the relationship between changes in affected arm volume and impedance ratios, there was a statistically significant correlation only at 5 kHz impedance. The results are consistent with previous studies in that ratios of SFBIA before CDT are useful tools for predicting responsiveness to treatment in BCRL patients. Unexpectedly, SFBIA of low frequency did not predict the outcomes better than that of high. Similar results were obtained in the analysis of the relationship between changes in affected arm volume and impedance ratios, showing a statistically significant correlation only at 5 kHz impedance. Further study will be needed to find out other factors to be considered.