Background: Most commonly, volume measurements are used to evaluate the effect of lymphedema treatment, but as the accumulation of lymph fluid can be local, this method may not always be the best. Tissue dielectric constant (TDC) can be applied to identify local lymphedema changes, but has not been used before when evaluating treatment in mild arm lymphedema. Thus, the overall aim of this study was to examine if TDC and water displacement method (WDM) can measure changes in mild breast cancer-related lymphedema during the 6-month standard treatment. More specifically, we examined changes within and between three defined groups based on lymphedema thresholds of TDC and WDM at start of treatment, as well as changes of the highest TDC ratio and site. Methods and Results: Forty-six women with mild arm lymphedema, received treatment with compression sleeves, mostly ccl 1, and instructions about self-care. Local tissue water was measured by TDC at six defined sites and lymphedema relative volume (LRV) by WDM before treatment and at first, second, third, and sixth month. There was a significant decrease in the site with the highest TDC ratio, as well as LRV at all follow-up visits. At 6 months, TDC ratio had decreased mean 0.26 (p < 0.001) and LRV mean - 3.3% (p < 0.001). There was a significant difference between the groups in change of TDC ratio, but not in LRV. Sixty percent changed the overall highest TDC ratio to another site during 6 months. Conclusion: Both TDC and WDM could detect changes in mild arm lymphedema but should be interpreted separately.
Keywords: arm lymphedema; breast cancer; tissue dielectric constant; treatment; water displacement method.