Technical and Clinical Advances in Hyperthermia Treatment of Cancer

Abstract

Although significant improvements have been achieved in the treatment of cancer by surgery, chemotherapy and radiotherapy, control of local or regional disease is a common problem. Since approximately one third of patients who die of cancer have uncontrolled local or regional disease, it has been argued that worthwhile improvements in survival rates could be expected if the efficacy of the local therapy could be increased. During the past few years there has been increasing interest in investigating the role that hyperthermia may have in cancer therapy. Hyperthermia is therapy in which tissue temperature is elevated to 41°C or higher by external means in opposition to the thermoregulatory processes which control body temperature around the normal set-point. The biological rationale for using hyperthermia is related to the ability of heat to destroy, in a virtually selective manner, malignant cells situated in a physiologically deprived environment and to act as a direct sensitising agent to the effects of ionising radiation. Clinically, the combination of hyperthermia and radiotherapy has led to improvement of irradiation treatment of some advanced tumours in an ever increasing number of studies. However, the true potential of hyperthermia remains to be determined by the outcome of controlled clinical trials. A prerequisite for such trials is availability of equipment which is capable of delivering and monitoring treatments in a safe, effective and predictable manner. This is a major challenge particularly when dealing with tumours deep in the body. However, significant improvements to the technology associated with hyperthermia have been made in recent years and some clinical trials involving the treatment of patients with superficial tumours are now underway.