Freezing tumors eases cancer pain in study

Freezing tumors eases cancer pain in study
CHICAGO (Reuters) - Freezing tumors may help relieve theextreme pain of cancer that has spread to the bone, which isoften untouched by narcotics or radiation, U.S. researcherssaid on Tuesday.
This freezing process, called cryoablation, is often usedto destroy kidney, prostate and other tumors, but researchersat the Mayo Clinic in Rochester, Minnesota, found it easedcancer pain in 80 percent of patients in a small study, and theeffect lasted for up to six months.
About 100,000 people in the United States each year havecancer that metastasizes, or spreads, to the bones. Radiationtherapy is the most common treatment for localized pain inmetastatic cancer.
"Two key parts of this study are that the reduction in painlasts and their quality of life improves after receiving thetreatment," Dr. Matthew Callstrom, a radiologist, said in astatement. He presented his results at the annual meeting ofthe Radiological Society of North America in Chicago.
The study, funded by medical device maker Endocare Inc,involved 34 patients who had failed to find relief fromconventional pain management treatments or refused them.
They had different primary cancers, including colorectal,renal cell, ovarian, thyroid and melanoma -- all of which hadspread to the bone.
Doctors used CT imaging scanners to guide tiny, needle-likeprobes to the tumor. Argon gas was then injected through a tinytube into a larger chamber in the probe, causing it to becomecold enough to freeze the tumor.
"You have very good control and you can see exactly whatyou are doing," Callstrom said in a telephone interview.
Patients in the study started out with an average painscore of 7.2 on a scale of 10, which is considered moderatelysevere. That was reduced by roughly half (about 3.6) eightweeks later. For patients followed for 24 weeks, the scoredropped to an average of 1.7.
"That's a pretty good drop in their pain," said Callstrom,who was not paid by Endocare.
"The technique is very well tolerated. It does not increasepain and you can do it with very high precision."
He and colleagues plan to study the pain managementapproach in a larger study funded by Endocare and the NationalCancer Institute, comparing cryoablation and radiation.
(Editing by Maggie Fox and Mohammad Zargham)