Freeze or Heat Cells to Fight Cancer
Cancer Cells Killed With Techniques That Use Heat or Cold, Studies Shows
March 17, 2008 -- Researchers are running hot and cold on cancer treatment.
New studies suggest that freezing tumors -- and in other cases heating them -- could mean quicker and less invasive treatment for some cancer patients.
In one technique, surgeons use a thin probe to quickly freeze cancer cells in patients with renal cell cancer -- the most common type of kidney cancer. The procedure kills the cancer cells, says Christos Georgiades, MD, interventional radiologist at Johns Hopkins Hospital in Baltimore.
Georgiades used the technique -- called cryoablation -- in 65 patients who had kidney tumors about 3 centimeters in size, on average. He says the procedure had a 97% success rate in patients whose tumors were less than 4 centimeters in size.
Researchers at Wayne State University used a similar procedure to treat 90 kidney cancer patients for a 94% success rate.
Doctors guide the probe to the tumors using a CT scan, performing the procedure in a radiology suite rather than an operating room.
Georgiades says targeted freezing could be a viable option for cancer patients who can't have more invasive surgery because of the dangers of general anesthesia. Patients with heart or lung disease often can't go to the operating room because of the risks.
"Half the patients treated have this procedure on an outpatient basis; they went home the same day," Georgiades told reporters at a conference of the Society of Interventional Radiology conference in Washington, D.C.
Still, the results are preliminary. Only half of his patients have been followed for at least one year. It's unclear how many of the cancers will come back as time goes on.
Killing Cancer Cells With Heat
Meanwhile, researchers in France are taking a similar -- though much hotter -- approach to small lung cancers. They're using a thin probe to quickly heat up cancer cells and kill them.
The probe has a fan of thin filaments at its tip that use radiofrequency energy to heat cells up to 60 degrees Celsius (140 degrees Fahrenheit).
"It's very close to a microwave at home," says Thierry de Baere, MD, a researcher at the Institut Gustave Roussy in Villejuif, France.
Radiofrequency ablation has never been directly compared to traditional surgery. But Thierry says that 70% of his patients were still alive after two years vs. an average of 48% in similar patients who can't have surgery because of the extent of their disease or other health problems. They were able to completely destroy about 90% of the tumors, he says.
For patients who can have traditional surgery, de Baere says his results are comparable. But the advantage may be convenience and fewer side effects. About two-thirds of patients were able to leave the hospital within two days of their radiofrequency procedures, he says. About 12% had to have a chest tube put in because of an injury caused by the probe.