The effect of modulated electro-hyperthermia on temperature and blood flow in human cervical carcinoma.

INTRODUCTION: Mild hyperthermia has been known to enhance the response of tumours to radiotherapy or chemotherapy by increasing tumour blood flow, thereby increasing tumour oxygenation or drug delivery. The purpose of this study was to assess the changes in temperature and blood flow in human cervical cancer in response to regional heating with modulated electro-hyperthermia (mEHT). METHODS: The pelvic area of 20 patients with cervical carcinoma was heated with mEHT. The peri-tumour temperature was measured using an internal organ temperature probe. The tumour blood flow was measured using 3D colour Doppler ultrasound by determining the peak systolic velocity/end-diastolic velocity ratio (S/D ratio) and the resistance index (RI) within blood vessels. RESULTS: The mean peri-tumour temperature was 36.7 ± 0.2 °C before heating and increased to 38.5 ± 0.8 °C at the end of heating for 60 min. The marked declines in RI and S/D values strongly demonstrated that heating significantly increased tumour blood perfusion. CONCLUSIONS: Regional heating of the pelvic area with mEHT significantly increased the peri-tumour temperature and improved the blood flow in cervical cancer. This is the first demonstration that the blood flow in cervical cancer is increased by regional hyperthermia. Such increases in temperature and blood flow may account for the clinical observations that hyperthermia improves the response of cervical cancer to radiotherapy or chemotherapy.