U of MN research indicates why radiation therapy reduces bone cancer pain

Although physicians administer radiation therapy to relieve bone cancer pain in more than 100,000 patients each year in the United States, little is known about why the treatment works. Using an experimental radiation model, University of Minnesota Cancer Center researchers and colleagues have determined that radiation treatment may relieve pain by reducing bone tumor size and decreasing progression of cancer-induced bone destruction. The findings appear in February issue of the journal Radiation Research.

"Perhaps the greatest obstacle to improving pain relief following radiation of bone cancer is our limited knowledge regarding mechanisms responsible for decreasing the pain," said lead investigator Denis Clohisy, M.D., professor of orthopedic surgery in the Medical School and Cancer Center member. "Future use of the experimental system described in this research should help accelerate the pace of discovery around these mechanisms and help efforts to reduce the burden of pain suffered by bone cancer patients."

Researchers in this investigation created an experimental model that limited radiation to the site of cancer in mice and then used an established bone pain model, imaging techniques, and histologic evaluations to understand the effects of radiation.

The research demonstrated that a localized, single radiation dose decreased painful behavior and increased limb use, which was associated with a decrease in bone destruction and tumor burden. Treated mice demonstrated greater pain relief and had significantly less bone destruction and tumor burden than untreated mice. Recent studies have demonstrated that tumor burden and bone destruction each correlate with behavioral and neurochemical measures of pain.

Co-authors of this study are Bruce J. Gerbi, Ph.D., Parham Alaei, Ph.D., Patrick W. Mantyh, J.D., Ph.D., Michael Goblirsch, B.A., Wendy E. Mathews, B.S., and Christine Lynch, B.S.

The Cancer Center at the University of Minnesota is a National Cancer Institute-designated Comprehensive Cancer Center. Awarded more than $80 million in peer-reviewed grants during fiscal year 2003, the Cancer Center conducts cancer research that advances knowledge and enhances care. The center also engages community outreach and public education efforts addressing cancer. To learn more about cancer, visit the University of Minnesota Cancer Center Web site at http://www.cancer.umn.edu. For cancer questions, call the Cancer Center information line at 1-888-CANCER MN (1-888-226-2376) or 612-624-2620 in the metro area.

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