Ultrasound may find roles in treating cancer, bleeding

By Warren King
Seattle Times medical reporter

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A new technique focuses ultrasound's high-frequency sound waves so intensely that they produce tissue-damaging heat, researchers said yesterday in Seattle at the annual meeting of the American Association for the Advancement of Science.

"There will be cancers for which it will revolutionize treatment," said Gail ter Haar, a researcher at Royal Marsden Hospital in London. "But we are a long way off from that now."

Physicians hope the new technique will replace the surgeon's knife and radiation for some cancer patients, and stop bleeding in trauma patients. They believe it can do its work without damaging healthy tissue that surrounds the problem area.

The technique is most advanced in the treatment of prostate cancer. French scientists say an overall 65 percent of the 242 men they have treated in a study are free of the disease after 20 months. These include patients with tumors still inside the prostate gland and those with cancer slightly beyond the gland.

About 60 percent of the men (with an average age of 71) were impotent after the treatment, and 8 percent were incontinent, said Jean-Yves Chapelon, of the French National Institute for Health and Medical Research. The chances of impotence with current prostate surgery vary widely: anywhere between 20 and 90 percent, depending on age, extent of disease, and type of surgery.

Physicians use a probe inserted through the rectum to image and send the ultrasound waves into the prostate. Chapelon said the method requires a shorter hospital stay and costs less than surgery. It is being tested in the U.S. by Focus Surgery of Indianapolis.

Studies of brachytherapy, in which radioactive seeds are implanted in the prostate for tumors that haven't spread, show 60 to 90 percent of men cancer-free after four to five years.

Ter Haar said the earliest tests using the technique for treatment of liver and kidney cancers have shown great promise and have proven safe. "We can treat tumors deep in the body without any damage to other tissue," she said in a news conference with other scientists.

Trials haven't been conducted yet to determine how effective the technique is in curing the cancers, but tumors surgically removed after the experimental ultrasound treatment show it is effective in destroying tissue. Ter Haar predicted the treatment would be widely available in five to 10 years.

Because ultrasound cannot penetrate bone, it would be difficult to use for some cancers, including lung and brain tumors, she said.
 
At the University of Washington, Shahram Vaezy, research assistant professor of bioengineering, and his colleagues are experimenting with high-intensity ultrasound to stop bleeding from wounds and internal bleeding. Heat from the beam both cauterizes the damaged area and helps induce the blood to clot.

Eventually, the UW researchers hope to develop ultrasound equipment small enough to be used at accident scenes or on the battlefield. The U.S. Department of Defense has financially supported some of the research.

Vaezy said ultrasound probably would not work on massive bleeding. But it might well work, for example, on a bleeding liver, which has many blood vessels and often is damaged in serious auto accidents.

"At the accident scene, the device would detect if the liver is bleeding, then focus on the site and stop the bleeding," said Vaezy.

Vaezy said researchers hope to begin testing the technique at Harborview Medical Center within two years.

Warren King: 206-464-2247 or wking@seattletimes.com

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