Temperature distribution and pH changes during hyperthermic regional isolation perfusion

Hyperthermic perfusion was given as a palliative treatment in three patients with a bulky tumour in the leg. During the treatment, temperature and pH data were collected in both tumour and normal tissues. The hyperthermia dose administered was 2 h at 41.9-42.7 degrees C. It was found that the temperature distribution was far from homogeneous. In one case tumour pH could be monitored throughout the whole treatment procedure. The tumour pH showed a steep decrease during the initial phase of the perfusion, from a mean value of 7.11 to 5.94 at the start of the hyperthermic phase. Subcutis pH decreased only 0.29 units during the whole procedure. In all three patients considerable tumour regression was observed, without severe toxicity. Hyperthermic perfusion appeared to be an effective debulking treatment. The pH decrease in tumour tissue, immediately before hyperthermia, may be responsible for the remarkable effectiveness of the hyperthermic treatment.