'Microwaving' Tumors May Treat Cervical Cancer

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Microwave heat — delivered by a futuristic machine — may one day become part of the standard treatment for advanced cervical cancer.

The finding comes from 68 cervical cancer patients treated in the U.S., the Netherlands, and Norway. All patients were treated with state-of-the-art chemotherapy and radiation treatment. They were also treated with a special microwave that heated their pelvic regions to about 104 degrees Fahrenheit.

Ninety percent of the patients had a complete remission of their cancer. A year and a half later, 84 percent were still alive, Anneke M. Westermann, MD, PhD, of the Academic Medical Center in Amsterdam, and colleagues report in the Aug. 15 issue of Cancer.

That's pretty good, says cervical cancer expert Wui-Jin Koh, MD, professor of radiation oncology at the University of Washington and Fred Hutchinson Cancer Center, Seattle. Koh was not involved in the clinical trial.

"If you look at chemoradiation by itself, you would say the five-year overall survival rate for advanced cervical cancer would be percentages in the high 60s to low 70s," Koh tells WebMD. "That is at five years. So the question is whether their median survival of 84 percent at a year and a half will hold."

Hyperthermia isn't new. It's been known for years that cancer cells die at high body temperatures. The FDA has already approved microwave treatment for superficial cancers on or near the skin.

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Advancing Technology

The newer microwave machine used in the current study is more advanced, says Paul Turner, chief technical officer for device maker BSD Medical Corp.

"It lets us focus energy from many antennas positioned around the body, so we can direct the energy in a noninvasive way to any body part," Turner tells WebMD. "We can reach deep into the pelvis and even into the thorax."

In a major clinical trial, the device already showed that it can greatly improve radiation therapy. But chemotherapy improves radiation therapy just as well. And chemotherapy has the added advantage of reaching throughout the body to hit cancer cells that may have wandered far from the original tumor site.

That's why chemoradiation is the standard of care for advanced cervical cancer, Koh says. It's also why the makers of the microwave device have turned their attention to seeing if microwave hyperthermia makes chemoradiation more effective.

"We are combining all three to give a super therapy a major punch," Turner says.

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Big Test Already Under Way

Is it going to work? The current study shows that it might. Most patients tolerated the triple treatment well. But it wasn't easy. The most common side effects were white-blood cell anemia (leukopenia), fatigue, nausea, vomiting, and diarrhea.

The microwave caused pain in five patients, very slight burns in 12 patients, and mild signs of a worrisome side effect called subcutaneous fatty necrosis. None of these side effects was serious enough to cause doctors to withhold the treatment.

But chemotherapy and radiation are famously difficult to endure. Will adding hyperthermia be worth the effort for patients?

"I would worry about patients," Koh says. "With chemo and radiotherapy you are already pushing people to what would be considered the limits of tolerance. … My concern is if you add hyperthermia, they may go beyond the limits of patient tolerance."

But Koh quickly adds that if hyperthermia makes treatment more effective, it would certainly be worth it.

"With chemoradiation, at least 20 percent of patients have continued cancer spread in the pelvis or the tumor comes back at the primary site," he says. "The promise of hyperthermia is that it might improve pelvic control and reduce the overall remission rate. If this study holds true, this is worth testing."

Tests already are under way. An international clinical trial is randomly assigning 400 cervical cancer patients to either chemoradiation or chemoradiation plus microwave hyperthermia.

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By Daniel J. DeNoon, reviewed by Brunilda Nazario, MD

SOURCES: Westermann, A.M. Cancer, Aug. 15, 2005; vol 104: pp 763-770. Wui-Jin Koh, MD, professor of radiation oncology, University of Washington and Fred Hutchinson Cancer Center, Seattle. Paul Turner, chief technical officer, BSD Medical Corp., Salt Lake City.