Today's researchers are exploring several ways to make radiation therapy more effective, building on important advances in biology, physics and engineering. Some have already produced significant results.
Hyperthermia The effect of heat on some types of cancer has been observed for more than 100 years. In 1893, W. B. Cooley reported that high temperatures had an effect on 38 patients, 12 of whom had a complete regression of their cancers. Many malignant cells show a therapeutic response to high temperatures. And even moderate hyperthermia (42°C/108°F) can cause destruction of malignant cells.
Compared to radiotherapy alone, the combination of heat plus radiation has increased the response rate of certain tumors such as melanoma, and there are also promising preliminary results from treating brain tumors using interstitial implants plus heat.
Researchers are now studying the use of a new "multimodality" treatment—the combination of radiation therapy, chemotherapy and heat—which may increase the response rate for some tumors ( see Hyperthermic Perfusion Therapy ).
Clinical Modifiers Research continues in the hope of finding chemical compounds that will modify radiation effects. Since radiation is more effective in cells with a good oxygen supply, one of the first approaches to modifying radiation sensitivity was through the use of hyperbaric oxygen chambers. Patients were placed in a closed chamber so they could breathe air with a higher than normal concentration of oxygen.
