Knifeless surgery kills cancer
By Ed Susman UPI Science News
Published 2/15/2004 12:01 AM
SEATTLE, Feb. 15 (UPI) -- New,
experimental technology allows doctors to kill cancers deep inside the body with
high-intensity ultrasound instead of scalpels and other surgical instruments,
The procedure promises to give
patients too ill to face conventional surgery a chance to fight their disease,
and further applications of the technology -- called high-intensity focused
ultrasound -- someday could save the lives of accident trauma victims or
soldiers on the battlefield.
"We are in the very early days of
using this technique to treat liver cancers," said Gail ter Haar, head of
therapeutic ultrasound at London's Royal Marsden Hospital in the United Kingdom.
"But we are very excited about our results. This is not yet a cure for cancer,
but we have shown that we can treat tumors that are deep within the body without
She and her colleagues are
conducting tests with an ultrasound device developed at Oxford University by the
Chongqing HAIFU Technology Company, Ltd in China. They also are using their own
instrument at Royal Marsden Hospital.
Both systems employ conventional
ultrasound to locate a tumor in the liver or other organs. Then, the
high-intensity capacity is used to destroy the tumor.
"If you can image the tumor with
diagnostic ultrasound, you should be able to treat it," ter Haar told reporters
at the annual meeting of the American Association for the Advancement of
"In the same way as a magnifying
glass can be used in bright sunlight to set fire to dry tinder, sound energy can
be focused and used to raise tissue temperature to the point at which cells
die," ter Haar explained.
Basically the tumors are cooked to
death quickly. The focused sound energy raises the temperature to around 140
degrees Fahrenheit (60 degrees Celsius), killing the cells in about one second.
By targeting cells systematically in this manner, an entire tumor can be
destroyed, she said.
In order to perform the procedure,
doctors require something called an acoustic window, said Shahram Veazy,
research assistant professor of bioengineering at the University of Washington's
Applied Physics Laboratory. The ultrasound beam must travel through continuous
tissue or fluid to the tumor site because the energy cannot be focused through
gas or bone.
Veazy said the subsequent dead
tissue is then cleared by normal body functions. "Tissue amounts as much as a
small orange can be handled by the body," he explained.
Researchers have treated more than
3,000 patients in China with liver and pancreatic cancers. "The success rates
there are astounding," ter Haar said, adding her group is conducting studies in
London to bring scientific validity to the treatment.
At present, she said, the research
is using focused ultrasound as a palliative -- or pain-relieving -- treatment to
attack specific liver tumors in terminal patients with multiple tumors. She said
she has seen encouraging results in those patients. She added there is some
evidence -- albeit mostly anecdotal -- that killing one liver tumor provokes a
kind of "bystander" effect on other tumors in the organ, possibly because the
treatment evokes an increased immune response.
Researchers in France and
elsewhere in Europe have been using the system to treat prostate cancer and
other soft tissue tumors.
"We can say that ultrasound
surgery of prostate cancer is safe and effective with low risks," said Jean-Yves
Chapelon, director of research at the Institut National de la Sante et de la
Recherche Medicale in Lyon, France.
He said the procedure has shown it
can destroy cancerous tissue without harming adjacent healthy organs. It also:
-- does not require radiation;
-- shortens hospital stays;
-- allows for repeat treatments,
which often is not possible with radiation or chemotherapy, and
-- can be used in conjunction with
Veazy, working with grants from
NASA and the U.S. Department of Defense, said studies show the focused
ultrasound can be used to staunch blood flow quickly from severed blood vessels
though a process called acoustic hemostasis.
He said high-intensity focused
ultrasound can target a small area and, in a single second, encourage blood to
coagulate. It generates temperatures as high as 212 degrees F. -- the boiling
point of water -- which fuses the edges of cuts and tears in the skin.
"The machines we have now are big
and bulky," Veazy said, "but with miniaturization they could be taken on
ambulances to scenes of accidents and use to treat patients who are in danger of
bleeding to death."
In times of war or other
conflicts, he noted, the devices could be taken into combat zones and prevent
mortalities. About four in 10 deaths on the battlefield are due to the inability
to halt bleeding.
Veazy said the future version of
focused ultrasound devices might be found in operating rooms, doctors' offices
and even at animal clinics for use by veterinarians.
Chapelon cautioned that acceptance
of new devices and treatments tend to proceed slowly within the medical
community. Nevertheless, he predicted widespread use of the devices -- some of
which are becoming commercially available in Europe, China and elsewhere -- will
be seen in 10 to 15 years.
Ed Susman covers medical research
for UPI Science News. E-mail email@example.com
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