Freezing the Pain of Cancerous Tumors

Cryoablation Offers Relief When All Else Fails

By Charlene Laino
WebMD Health News

Reviewed By Louise Chang, MD

Nov. 27, 2007 (Chicago) -- Doctors are freezing the pain out of agonizing tumors.

In a study of 34 cancer patients, the method, called cryoablation, alleviated relentless pain that hadn't respond to all other treatments.

"This was really severe, persistent pain that required patients to take narcotics just to get through the day," says researcher Matthew Callstrom, MD, PhD, a radiologist at the Mayo Clinic in Rochester, Minn.

All reported at least some pain relief. All were able to cut back on, and in some cases even stop taking, narcotics.

Most importantly, Callstrom tells WebMD, was the improvement in their quality of life.

"Patients said, on average, that half their life was affected by pain at the start of the study. By 24 weeks later, it was down to 10%," he says.

The findings were presented at the annual meeting of the Radiological Society of North America.

Probes Guided Through Skin

The minimally invasive technique involves inserting tiny probes called cryoapplicators through a quarter-inch cut in the patients' skin, using ultrasound or CT imaging to guide them into the tumor.

Gas is then circulated through the probes. When exposed to the probe's steel tip, the gas rapidly cools and freezes the area. Freezing destroys the cancer cells, inflammatory cells, and small sensory nerve cells that cause pain.

The new study involved 34 patients with a range of cancers including colorectal, kidney, lung, and ovarian. All were gravely ill with aggressive cancer that had spread to the bone.

According to Callstrom, about 200,000 Americans with cancer have poorly controlled pain due to bone spread each year.

At the start of the study, their pain score averaged 7.2 points on a 10-point scale. Four weeks later, pain was significantly reduced. The treatment appeared to have lasting effects: 24 weeks after undergoing the procedure, the average pain score was just 1.7 points.

A number of the patients died during the 24-week study, but that wasn't unexpected since all were considered terminally ill. Cryoablation is not designed to restore health or cure cancer, but to reduce physical suffering, Callstrom says.

The work was funded by Endocare Inc., which makes the cryoablation system used in the study.

Cryoablation vs. Radiation

Based on the results, the researchers were awarded a grant from the National Cancer Institute to lead a nationwide study to pit cryoablation against radiation therapy, the current gold standard for treating pain associated with advanced cancer that has spread to the bone.

Damian Dupuy, MD, a professor of radiology at Brown University who has also studied cryoablation, tells WebMD that radiation is probably a better option for most patients.

"Often the cancer has spread to many different sites. Radiation can hit many sites at once, but if you do cryoablation, you'll have probes all over the place. The patient will end up looking like a pincushion," he says.

But there is a sizable minority -- nearly 25% -- for whom cryoablation may prove the better option, Dupuy says.

"That's why we need to do the study," he says.

SOURCES: Radiological Society of North America 93rd Scientific Assembly and Annual Meeting, Chicago, Nov. 25-30, 2007. Matthew Callstrom, MD, PhD, assistant professor of radiology, Mayo Clinic, Rochester, Minn. Damian Dupuy, MD, professor of radiology, Brown University, Providence, R.I.

© 2007 WebMD Inc. All rights reserved.



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