MRI-Guided Cancer Surgery
ROSSLYN, Va., April 16, 1997---After repeated surgery, doctors told North Canton, Ohio, Mayor William Hines there was nothing else they could do about his cancer. That was a year ago. Today the tumor is gone and his life is back to normal.
Hines is one of seven patients to undergo an experimental procedure for kidney cancer at Case Western Reserve University. The Phase I clinical trial, led by Jonathan Lewin, M.D., aims to assess the procedureÃs safety and feasibility. The study focuses on patients with isolated kidney tumors smaller than a tennis ball and no other hope.
In the procedure, Lewin inserts a probe resembling a hypodermic needle into the patientÃs abdomen. He guides the tip of the probe into the heart of the tumor using magnetic resonance imaging (MRI) techniques designed in the laboratory of biomedical engineer Jeffrey Duerk, Ph.D.
The probe emits radio waves that heat and kill tumor cells. Watching the MRI video monitor, doctors can adjust the instrument to reach all parts of the malignancy while avoiding healthy tissue. As the physicians work, they can actually see the tumor die.
Hines, whose previous surgeries sidelined him for weeks at a time, rested in the hospital overnight after the experimental procedure and returned to his law practice in two days.
Since then, six other patients have followed. Disease progression was stopped in two patients and slowed in two others. A fifth continues to spawn new tumors, which are being treated. The sixth and most recent patient is doing well, but it is still early.
Duerk and Lewin are presenting their scientific methods and clinical results this week at the Fifth Scientific Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine in Vancouver, British Columbia.
Lewin is encouraged by the early results because kidney cancer is so devastating. Most patients cannot withstand surgery and do not benefit from chemotherapy. They are usually given six months to live.
"So for these patients, we have set the clock back," Lewin said. "And they can go back to work in a day or so with a minimum of discomfort."
Until recently, MRI was used only for diagnosis. Now doctors in a handful of medical centers around the country are experimenting with the imaging technology as a tool in the operating room.
The Case Western group, funded in part by a $736,000 Whitaker Foundation grant, is apparently the first to use an MRI-guided radio-frequency probe to destroy abdominal tumors.
"A handful of groups have looked at radio-frequency ablation for tumors," Lewin said. "For the most part, this has been done with ultrasound or CT to place a probe in a patient using an amount of energy that is expected to treat the tumor. Then they follow up with some kind of imaging to see if it was successful.
"In our protocol, we can interactively vary the energy and position of the probe with MRI guidance and monitor cell death as it happens," he said. "We can also guard against damaging vital structures."
The procedure relies on a Siemens open MRI machine coupled with a high-resolution, shielded LCD monitor. DuerkÃs group has rewritten the software that drives the machine so it can make images more rapidly. As a result, the image acquisition rate has risen from one frame every two minutes to one per second.
The addition of a three-camera array allows doctors to follow the precise position of the radio-frequency probe in three-dimensional space. "We can track the exact location of the tip of the probe and see whatÃs behind it as well," Duerk said.
The group hopes to begin a Phase II clinical trial for efficacy as early as next fall.
-- Contact: Frank Blanchard (703) 528-2430, [email protected]
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