Abstract: Far-Infrared Radiation Thermotherapy Improves Tissue Fibrosis in Chronic Extremity Lymphedema

BACKGROUND Fibrosis can enhance the exacerbation of lymphedema, which becomes obvious in late stage II-III lymphedema. However, whether far-infrared radiation thermotherapy (FIRT) can cure lymphedema fibrosis is still lack of research. This research was to investigate the therapeutic effect of FIRT on tissue fibrosis in the treatment of Late stage II-III lymphedema. METHODS Patients accepted only FIRT for a total of 20 sessions. The treatment session duration was 2 hours, and a stable machine temperature of 42°C was maintained throughout treatments. Clinical evaluation and laboratory evaluation were conducted before and after FIRT. Clinical outcome measures included circumference of affected extremity, skin elasticity, ultrasound, patients' subjective assessment, and quality of life (QOL). Laboratory outcome measures included serum and local lymphedema tissue fluid concentrations of fibrosis associated cytokines, tissue growth factor beta-1 (TGF-β1), interleukin (IL)-1β, IL-4, IL-18, and caspase-1. RESULTS Between 2015 and 2016, clinical evaluation of 64 patients with late stage II-III lymphedema was conducted. From this group, 12 cases (18.75%) underwent simultaneous laboratory evaluation. Circumferences of affected extremities improved significantly following treatment (p < 0.001). Skin elasticity of the affected extremity improved significantly (p < 0.05). Ultrasound investigation showed reduced fiber and dense material in the affected tissue (increased gray level 6.322% ± 7.624%, p < 0.001). Patients reported a subjective improvement of their symptoms such as decreased tightness, heaviness, solidity, pain, discomfort, and numbness (p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, and p = 0.032, respectively) and improved QOL (p < 0.001). Laboratory results revealed a significant decrease in local tissue fluid concentrations of TGF-β1 (p = 0.041) and IL-18 (p = 0.049) after course completion. CONCLUSION FIRT provides an effective treatment for lymphedema tissue fibrosis; it reduces the concentration of fibrosis cytokines in local lymphedema tissues. Consequently, this treatment can reduce the density of fibrosed tissue in the affected extremity, increase skin elasticity, significantly improve clinical symptoms, and improve QOL of patients.