TISSUE DIELECTRIC CONSTANT (TDC) MEASUREMENTS AS A MEANS OF CHARACTERIZING LOCALIZED TISSUE WATER IN ARMS OF WOMEN WITH AND WITHOUT BREAST CANCER TREATMENT RELATED LYMPHEDEMA

Abstract

Quantitative measurements to detectlymphedema early in persons at-risk for breastcancer (BC) treatment-related lymphedema(BCRL) can aid clinical evaluations. SinceBCRL may be initially manifest in skin andsubcutis, the earliest changes might best bedetected via local tissue water (LTW)measurements that are specifically sensitiveto such changes. Tissue dielectric constant(TDC) measurements, which are sensitive toskin-to-fat tissue water, may be useful for thispurpose. TDC differences between lymphedematousand non-lymphedematous tissue hasnot been fully characterized. Thus we measuredTDC values (2.5 mm depth) in forearms ofthree groups of women (N=80/group): 1)healthy with no BC (NOBC), 2) with BC butprior to surgery, and 3) with unilaterallymphedema (LE). TDC values for all armsexcept LE affected arms were not significantlydifferent ranging between 24.8 ± 3.3 to 26.8 ±4.9 and were significantly less (p<0.001) ascompared to 42.9 ± 8.2 for LE affected arms.Arm TDC ratios, dominant/non-dominantfor NOBC, were 1.001 ± 0.050 and at-risk/contralateral for BC were 0.998 ± 0.082 withboth significantly less (p<0.001) than LEgroup affected/control arm ratios (1.663 ±0.321). These results show that BC per se doesnot significantly change arm LTW and thatthe presence of BCRL does not significantlychange LTW of non-affected arms. Further,based on 3 standard deviations of measuredarm ratios, our data demonstrates that an atriskarm/contralateral arm TDC ratio of 1.2and above could be a possible threshold todetect pre-clinical lymphedema. Furtherprospective measurement trial are needed toconfirm this value.