Turns out that microwaves on campus can do more than make Easy Mac-and the National Cancer Institute agrees.
Researchers at the Duke University Medical Center recently received an additional $19-million grant to continue studying the efficacy of treating cancer with heat.
The program represents the only federally funded hyperthermia research program in the United States. The research aims to refine the methods of delivering heat to cancer tissue.
Dr. Mark Dewhirst, professor of radiation oncology and director of the hyperthermia program, initiated the research program 19 years ago. His experiments and results show that heat, combined with other treatments such as chemotherapy, can shrink and destroy tumors.
"Hyperthermia has the potential for helping patients with many kinds of locally advanced diseases," Dewhirst said.
Experiments have shown that the application of heat to a tumor in addition to conventional treatments can increase drug uptake and help shrink tumors.
The heating of tissue is accomplished by using directed microwaves, Dewhirst said. It both inhibits the ability of cells to repair damage and impairs the oxygenation of the tumor-a protective feature.
One of the most promising applications that Dewhirst and his team have designed is a heat-sensitive liposome that delivers a drug to a targeted, heated region of the body. The liposome, a biological locket of sorts, melts when exposed to a certain temperature and becomes leaky, delivering the drug it contains.
"We can deliver about 30 times more drug to a tumor than a free drug can," Dewhirst said.
In a preclinical trial, cancer-afflicted mice that were administered the free drug showed no effect, but mice that were treated with the liposome and hyperthermia were cured, Dewhirst said. He added that ultimately the liposome, which is currently in National Institutes of Health human trials, might be used to treat locally advanced breast cancer in which tumors have developed on the chest wall and are inoperable.
Another area in which hyperthermia has shown promise is the treatment of melanomas, said Dr. Doug Tyler, a clinician who has been participating in the research.
Tyler explained that when a melanoma that has been treated comes back, it returns in the form of multiple tumors-a situation that impedes surgical treatment and necessitates the use of a different treatment such as chemotherapy and hyperthermia.
"When it works, it works beautifully," Tyler said. "It can make these multiple tumors go away impressively."
But one of the major challenges researchers have faced is predicting when hyperthermia will help. "We have to be able to quantify the treatment," Dewhirst said.
To do so, the researchers have been developing non-invasive thermometry that measures the temperature of an area while it is being heated.
One procedure uses heating devices within a magnetic resonance imaging apparatus, which allows the doctors to extrapolate a measure of temperature from the movement of water.
"The biggest challenge is to make it a type of therapy that can be given relatively easily," Dewhirst said.
Ideally, the researchers want to make hyperthermia a treatment that can be prescribed in conjunction with others.
For now, however, the medical center remains one of the few places in the world where patients can receive the promising treatment-a circumstance that will continue thanks to the NCI's vote of confidence in granting the funds.
"For most diseases, this would be the only place you can get it in the United States," Dewhirst said.
Diseases that are being targeted for hyperthermia treatment trials include soft tissue sarcomas, locally advanced cervical cancer, locally advanced breast cancer and melanomas.
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