ROCHESTER, Minn. -- Mayo Clinic Cancer Center has begun three clinical studies looking at the use of nonsteroidal anti-inflammatory drugs (NSAIDs) to prevent cancer -- colon, esophageal or lung. These studies are part of the ongoing Cancer Center chemoprevention program, using medications to prevent cancer, especially for people with increased cancer risk.
“While searching for the cure is important, even more so is finding effective ways to prevent cancer,” says Paul Limburg, M.D., M.P.H., Mayo Clinic gastroenterologist and lead researcher on the colon cancer prevention study. “We have observed that some of the same biological processes that cause inflammation may also be involved in developing cancer, so the next step was to see if drugs that prevent inflammation also serve to lessen the risk of cancer.”
The colon cancer study is looking at the NSAID sulindac (Clinoril®), and its ability to inhibit inflammation and subsequent transformation of damaged cells into cancer cells. Sulindac’s preventive effect will be measured against that of two other potential prevention agents: atorvastatin (Lipitor®), a cholesterol-lowering drug with some reported cancer prevention aspects (Cancer Research, April and July 2006); and Raftilose®Synergy1, a food supplement derived from chicory, also with some supporting research conducted overseas (The British Journal of Nutrition, April 2005).
Dr. Limburg’s team will treat patients at increased risk for developing colon cancer, specifically individuals age 40 or older who have advanced colorectal adenoma (precancerous tissues) or a history of colon cancer with treatment completed more than one year prior to entering the study. Tissues and blood samples will be tested pre-treatment and post-treatment to determine the preventive effects of the different medications.
Other gastroenterologists at Mayo are looking at NSAID use for patients with Barrett’s esophagus. “There is evidence to support the idea that taking an NSAID will slow or reverse precancerous conditions such as Barrett’s esophagus,” Dr. Limburg says. “Prognosis for esophageal cancer patients is poor. We are continually looking for ways to prevent this and other cancers from ever starting, and NSAIDs provide a promising avenue for our research.”
Individuals eligible for the esophageal cancer prevention study will receive esomeprazole (Nexium®), an acid reflux medication, and aspirin, an NSAID. Mayo’s doctors hope that using the acid reflux medication will diminish inflammation caused by acid reflux and that the aspirin will continue the healing and prevention process. Tissue in the esophagus will be tested before and after treatment to determine the benefits, if any.
The lung cancer prevention study is directed at current or former heavy smokers, age 45 or older, who are in generally good health. Those in cancer remission may be eligible to participate, if their last treatment was at least one year ago. This study is also using sulindac, which will be administered to patients with abnormal, precancerous tissues in their lungs. Pre-drug and post-drug treatment tests will determine effectiveness by reviewing the degree of abnormality of the patients’ lung tissues after treatment.
“We have high hopes for all of these studies,” says Dr. Limburg. “Previous work has shown that these are promising prevention avenues to pursue, and, if positive, the findings could result in substantial benefit to patients and society from a decreased cancer burden.”
Mayo Clinic Cancer Center is offering the clinical studies under the auspices of membership in the Cancer Prevention Network (CPN). Dr. Limburg is the primary investigator for CPN, which is a consortium of 35 community clinics, hospitals and medical centers throughout the United States and Canada. Mayo is the lead organization and research data center for the Cancer Prevention Network, which focuses much of its research efforts on the most wide-spread and deadliest cancers.
More information on cancer-related clinical studies ongoing at Mayo Clinic can be found at http://clinicaltrials.mayo.edu. Potential study participants can call 507-538-7623 for more information.
These research studies are assisted in part by Astra-Zeneca, Bayer, Boston Scientific, Fujinon, Olympus and Orafti, Inc.
Cancer targeted on many fronts. Mayo researchers join network focused on prevention
By Jeff Hansel
Researchers at Mayo Clinic have joined a network of health-care facilities working to prevent cancer rather than cure it.
Mayo has been working to prevent cancer for a long time, said Dr. Robert Jenkins, an associate director of the Mayo Clinic Cancer Center, but the new "Chemoprevention Network" is a more formal commitment recognizing a national push for increased research into prevention.
Mayo is now fighting cancer on multiple fronts. Researchers have also announced they kept mice from getting malignant melanoma by making a human antibody induce anti-tumor responses.
Jenkins, a pathologist, said both research methods are needed. Even if preventive agents are found for common cancers such as breast and prostate cancer, treatments such as chemotherapy and radiation will remain important, he said.
Preventive methods are unlikely to be developed for rare cancers, he said, because it won't make sense for everyone to take a preventive pill for pancreatic cancer, for example -- a debilitating and fatal illness that is also rare. That keeps more conventional treatment methods pertinent.
"We're not going to be able to have screening and preventive strategies for all the cancers," he said.
Cancer prevention targeted in lieu of a cure.
By Jeff Hansel
Mayo Clinic plans two clinical trials this fall to study whether cancer can be prevented. The clinic has developed "The Chemoprevention Network" with 32 other medical centers in the United States and Canada.
The network is one of five funded by the National Cancer Institute. It will participate in chemopreventive -- cancer preventive -- clinical trials of 50 to 200 people, testing things like compounds from food, or medicines already on the market for other uses.
The goal is to stop cancer before it starts.
"I think that treating cancer before it develops has huge potential to really be effective," said Dr. Paul Limburg, a Mayo Clinic gastroenterologist and principal investigator for the network.
Limburg said the first Mayo trial will enroll 112 people taking a grain-fiber powder, plus cholesterol-lowering and anti-inflammatory drugs, to prevent both polyps, which are cancer precursors found in the colon, and colon cancer.
The second trial, Limburg said, is for 132 patients with a long history of cigarette smoking. Trying to prevent lung cancer, researchers led by Mayo pulmonologist Dr. James Jett will use an enzyme-inhibitor to stop an enzyme believed to be involved in development of cancer in several organs.
"A number of the things we're looking at are drugs already available for other things," Limburg said. Fiber, green tea and vitamins also are examples, he said.
Hormel Institute in Austin, an independent research branch of the University of Minnesota, will be closely involved, Limburg said. Already, Mayo is making plans to test at least one Hormel food compound showing promise against cancer, both Mayo and Hormel confirm. Neither institution will say what it is. But green tea and ginger compounds studied by Hormel have both shown promise.
Once pre-clinical testing of purified food compounds shows they are safe and effective, Hormel researchers said, the compounds will be moved to clinical trials "in the shortest time possible."
Limburg said the first two trials will be Phase I and Phase II to show safety and efficacy in humans. If no cancer develops, studies will move to Phase III with a larger number of people. Limburg envisions a daily horse pill, of sorts, that people of high risk might someday take to ward off cancers.
"In those groups of patients it might make sense to have somebody take a nutritional supplement or a drug on a long-term basis to try and prevent cancers from forming," he said.