Investigation of frequency dependence of bioimpedance capacitance in patients with breast cancer-related lymphedema

Abstract

Bioimpedance analysis is a noninvasive, low cost intervention for the early diagnosis and evaluation of breast cancer-related lymphedema (BRCL). This study investigated the frequency dependence of capacitance, a marker of disease progression, in 27 patients with BRCL. Capacitance of the affected and unaffected sides of upper limbs was calculated from XC values obtained at several frequencies (5, 50, and 250 kHz). At all frequencies, there was a significant difference in capacitance between the affected and unaffected sides; however, this difference was most pronounced at 5 kHz. The Weibull plot of capacitance at 5 kHz showed linear distributions on the affected and unaffected sides with Pearson’s correlation coefficients of 0.97 and 0.98, respectively. Furthermore, the shape parameter obtained from the slope of the fitting line of the Weibull plot was α = 3.90 for the unaffected side, which is approximated by a Gaussian distribution. The capacitance on the affected side was also on the fitting line of the Weibull plot, and the shape parameter of the Weibull distribution was approximately 2 (α = 2.04). The capacitance on the affected side was statistically characterized by a Rayleigh distribution. The capacitance distribution in the upper extremity of patients with lymphedema changed from Gaussian to Rayleigh as lymphedema progressed.