Immunological Effect of Regional Hyperthermia for Liver Tumors.

Introduction : Regional hyperthermia is used in multimodal cancer therapy. In this report, the T-cell subset and NK-cell activities of lymphocytes in the peripheral blood of patients with chronic hepatitis or hepatic tumors (hepatocellular carcinoma and liver metastases) were monitored and analyzed to evaluate changes in the host immune function as a result of regional hyperthermia treatment. Subjects and Methods : The immune function (T-cell, B-cell, and NK-cell activities of lymphocytes) of 48 patients with chronic hepatitis, 9 patients with hepatocellular carcinoma, and 4 patients with liver metastases was measured. Furthermore, the CD4 and CD8 levels and the CD4/CD8 ratio in 13 patients with hepatic tumors treated with regional hyperthermia were monitored before treatment and after eight sessions. 48 patients with chronic hepatitis were evaluated as control for hepatic tumors and were not treated with regional hyperthermia. Regional hyperthermia was performed by means of an 8-MHz radiofrequency capacitive-heating device. The treatment time was 40-60 min. Regional hyperthermia treatment was given twice a week for 4 weeks. The clinical outcome in 9 patients with hepatocellular carcinoma treated with long-term regional hyperthermia (more than 10 sessions) is summarized. Results : The number of T-cells in patients with hepatic tumors was significantly higher than that in patients with chronic hepatitis (p <0.001), and that of B-cells was significantly lower (p < 0.005). An evaluation of the changes in T-cell subsets as the result of regional hyperthermia treatment for hepatocellular carcinoma showed that the CD4/CD8 ratio significantly decreased (p < 0.05), whereas the CD4 level decreased (p = 0.063) and the CD8 level increased (p = 0.088). In contrast, the NK-cell activities were not significantly influenced by regional hyperthermia. An evaluation of the changes in T-cell subsets as a result of regional hyperthermia treatment for liver metastases showed no change in immune function. Conclusion : Regional hyperthermia for hepatocellular carcinoma results in a decrease in the CD4/CD8 ratio and affects the host immune function.