BEIJING, Nov. 28 (Xinhuanet) -- The phrase "frozen to the bone" has taken on a whole new meaning because of a new treatment that freezes bone cancers untouched by narcotics or radiation, researchers said Tuesday.

    This freezing process, called cryoablation, is often used to destroy kidney, prostate and other tumors, but researchers at the Mayo Clinic in Rochester, Minn., found it eased cancer pain in 80 percent of patients in a small study, and the effect lasted for up to six months.

    About 100,000 people in the United States each year have cancer that metastasizes, or spreads, to the bones. Radiation therapy is the most common treatment for localized pain in metastatic cancer.

    "Two key parts of this study are that the reduction in pain lasts and their quality of life improves after receiving the treatment," Dr. Matthew Callstrom, a radiologist, said in a statement. He presented his results at the annual meeting of the 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 from conventional pain management treatments or refused them. They had different primary cancers, including colorectal, renal cell, ovarian, thyroid and melanoma — all of which had spread to the bone.

    Doctors used CT imaging scanners to guide tiny, needle-like probes to the tumor. Argon gas was then injected through a tiny tube into a larger chamber in the probe, causing it to become cold enough to freeze the tumor.

    Patients in the study started out with an average pain score of 7.2 on a scale of 10, which is considered moderately severe. That was reduced by roughly half (about 3.6) eight weeks later. For patients followed for 24 weeks, the score dropped to an average of 1.7.

    (Agencies)