101-AP-98
EMBARGOED UNTIL 1 P.M. PDT TUESDAY, AUG. 18, 1998
Contact: Andrew Porterfield
(949) 824-3969
[email protected]
UC IRVINE RESEARCHERS IDENTIFY DRUG THAT SHOWS PROMISE IN PREVENTING COLON CANCER
Irvine, Calif. - A team of UC Irvine researchers has found that an experimental chemotherapy drug that failed to treat colon cancer may arrest the development of the disease. Colon cancer kills 50,000 Americans a year and is second only to lung cancer as the nation's leading cause of cancer deaths.
Dr. Frank Meyskens, director of the UCI Chao Family Comprehensive Cancer Center, and his research team discovered that low doses of the drug, called difluoromethylornithine (DFMO), were effective at halting the metabolic activity that cancerous cells need to grow in the human colon. The team's findings will appear Wednesday, Aug. 19, in the Journal of the National Cancer Institute.
The work is unusual because it is the result of 10 years of research into the effects of DFMO. Such a large volume of data is not available in most cancer studies, said Meyskens, who will continue his research with a new study on whether DFMO prevents colon cancer more effectively when used in combination with another anti-cancer agent.
In the study to be published Wednesday, the researchers spent one year looking at 118 patients who had never been diagnosed with colon cancer, but had undergone surgery to remove a non-malignant polyp from their colons. The patients were given either varying doses of DFMO or an inactive placebo. The researchers found that low doses of DFMO slowed the production of molecules called polyamines, which are known to induce cancer-causing tumors.
Polyamines are found everywhere in the body, and at normal levels work to control cell growth. If too many polyamines are produced in an organ, however, they trigger a chain reaction that leads to abnormally rapid tissue growth. These rapidly growing tissues, or polyps, can transform easily into cancerous tumors in the colon and other organs. DFMO prevents this dangerous tissue growth by inhibiting an enzyme that spurs the production of polyamines.
The UCI researchers began looking at DFMO as a possible treatment for various cancers, including those in the colon, in the late 1980s. They found that the chemical did not eliminate cancerous cells in the colon. DFMO could not destroy the cancerous cells, Meyskens said, because the high volume of polyamines already produced by those cells overwhelmed any actions of the anti-cancer chemical.
But the research also showed DFMO's prevention potential. If further studies continue to demonstrate DFMO's effectiveness at preventing cancerous growth, the drug could be given to people at risk of colon cancer, possibly for their entire lifetimes. The doses of DFMO used in the UCI study produced few side effects among the study participants, Meyskens said.
"We're encouraged by these findings, which indicate that there's a possibility that someday DFMO could be useful in preventing colon cancer in the same way that aspirin and blood pressure medications have helped prevent heart disease," Meyskens said. "This is a sign of how the fight against disease-including cancer-is moving away from treatment and toward prevention. We are hopeful that our new study will show us how effectively this agent works in combination with other drugs to prevent colon cancer from occurring in the first place."
In the new study involving 250 patients who are at risk of developing colon cancer, half of the study participants will be given low doses of DFMO in combination with a drug called Sulindac, which typically is used to fight inflammation. The rest will be given a placebo. Previous studies have shown that combinations of certain anti-cancer chemicals can be more effective than a single chemical at halting the growth of precancerous polyps.
The research measuring how well the DFMO-Sulindac combination slows the growth of pre-cancerous polyps and cancerous tumors will take five years. Patients qualified to participate in the study will be seen at a number of clinic sites, including UCI Medical Center, Long Beach Veterans Association Medical Center, the Long Beach Gastroenterology Association, Loma Linda Veterans Administration Medical Center and the Arizona Cancer Center-University of Arizona.
The researchers will test male and female volunteers between ages 40 and 80 who have had a polyp removed within five years before entering the study, and had no cancer during that time. Study volunteers must also have had no severe metabolic disorders or other life-threatening disease, and no radiotherapy or chemotherapy. The study has other criteria for selecting volunteers, as well. People interested in participating in the study should call (714) 456-6485.
The new study will be led by Meyskens, Dr. Daniel Pelot of UCI's Gastroenterology Department and Dr. Philip Carpenter of UCI's Pathology Department.
Through its comprehensive approach to cancer research and treatment, both at the UCI Medical Center and the College of Medicine, UCI has emerged as a national leader in the fight against cancer. Last year, the National Cancer Institute awarded its most prestigious honor, the designation of "comprehensive cancer center," to the UCI Chao Family Comprehensive Cancer Center. In addition, UCI's Epidemiology Division recently was named the only California member of NCI's Cancer Genetics Network, which includes leading research institutions across the country that are studying how cancer is inherited. UCI also was selected to run the NCI Cancer Genetics Network Informatics Center, which will manage the information systems needed to support the network's research.
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