Sungmin Ro was dreading his second major surgery for liver cancer. The first procedure left him with a big scar across his abdomen and a long, painful recovery. "Fifty stitches," the 46-year-old Tampa man said, chuckling, "and four weeks out of work."
Most liver tumors can't be removed through traditional surgery. So doctors had to open Ro's abdomen to treat the tumor with ablation — the application of high heat (as in Ro's case) or freezing cold to destroy cancer cells. A second, smaller tumor near his gallbladder and major blood vessels couldn't be treated in the same way because it was so close to critical healthy tissue, which standard ablation can damage irreversibly.
But soon after Ro recovered from that initial operation, doctors at Tampa General Hospital began offering a new form of ablation using a system called the NanoKnife. It kills cancer cells not by cutting, as the name implies, and not with high heat or freezing cold but with pulses of electricity that don't damage nearby tissue. Plus, he wouldn't need another big incision.
Ro reported to the hospital on a Thursday in June, went home on Saturday and was back to work on Monday morning. "The difference was just night and day," Ro said.
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The NanoKnife, manufactured by AngioDynamics, was FDA approved in 2008 through a shortcut that allows for regulatory clearance — sometimes with little or no clinical evidence — if a device is similar enough to others already on the market. Though the NanoKnife eliminates cancer in a unique way, it met that criterion.
With the shortcut, NanoKnife was not put through long-term, rigorous clinical trials. So although doctors are enthusiastic about its use in limited applications, they caution that its track record isn't yet established.
Tampa General Hospital and Moffitt Cancer Center in Tampa have both had the system on loan for under a year and have each treated about 10 cancer patients who had small, difficult-to-reach tumors. Around the country, there are 40 systems in use. The University of Miami Medical Center has done the most procedures with it: more than 100.
"It's a valuable approach," said Dr. Junsung Choi, director of interventional radiology at Moffitt. "We can use it selectively where other forms of ablation may not work."
With the NanoKnife, usually two to four needles are inserted through the skin directly into or around cancerous tissue. A small external generator produces 90 quick pulses of electricity (between heartbeats), killing cancer cells in under five minutes.
"Right now the setup is the most time-consuming part of the procedure," said Dr. Cliff Davis, an interventional radiologist at Tampa General who was involved in Ro's care. "But it takes just two to five minutes to kill the cancer." Standard ablation can take up to 45 minutes.
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The NanoKnife is used primarily to treat liver and pancreatic cancers, but may also be effective for treating kidney, lung, prostate and brain cancers.
While promising, it has limitations. It's only effective on tumors smaller than 1 1/2 inches; any larger and cancer cells may be left behind. Choi adds that a single-needle procedure would be less painstaking and time consuming. Davis agrees: "It can take an hour and a half to place the needles and set everything up," he said.
"Plus, it hasn't been studied in large-scale groups of people yet over a long period of time," said Choi, "We need long-term followup to know if patients are cancer free years later."
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The technology is also expensive — the system costs hospitals $200,000; needles cost $2,000 each and can be used just once.
Not all insurance companies cover the treatment, since it doesn't have a strong track record.
"That's the problem with new technology," said Dr. Matthew Berlet, medical director of radiology at St. Joseph's Hospital in Tampa, which does not have the NanoKnife. "It has great potential but until it's fully vetted and accepted by insurance companies, it won't find its way to community hospitals. It will be limited to research hospitals."
The manufacturer is also still working out technical problems with the NanoKnife. AngioDynamics recently recalled computer software that helps doctors define the treatment zone, but local doctors say this won't stop their use of the device.
"We have other ways of pinpointing the area. This recall doesn't affect the effectiveness of the treatment," said Dr. Bruce Zwiebel, director of vascular and interventional radiology at Tampa General.
Eight months after his treatment, Ro is cancer free. He doesn't mind showing people the scars from each procedure. One is long. The other "looks like a mosquito bite."
Irene Maher can be reached at [email protected]