RENEE MONTAGNE, host:
There's new evidence that a widely used drug for heart disease might also prevent colon cancer. The study appears in this week's New England Journal of Medicine. Still, as NPR's Patricia Neighmond reports, the research isn't conclusive.
PATRICIA NEIGHMOND reporting:
Researchers from the University of Michigan and from Israel wanted to know if cholesterol-lowering statin drugs might prevent colon cancer. They looked at the medical records of nearly 4,000 patients. About half had colon cancer; half did not. Researchers then checked to see how many in both groups had been taking statins. Oncologist Ernie Hawk of The National Cancer Institute reviewed the study and wrote an editorial on it.
Dr. ERNIE HAWK (The National Cancer Institute): This study showed about a 50 percent reduction in colon cancer risk among those who use statins.
NEIGHMOND: That's good news, but Hawk says its value is limited because of the study's design.
Dr. HAWK: The studies where you look at a population, look at users or non-users of a drug as was done here and identify associations with cancer or some other disease are very useful to lay the foundation for future research but they don't answer the questions with enough detail to make specific recommendations.
NEIGHMOND: In order to confidently advise patients, Hawk says studies need to look forward and ensure there are no other factors that could contribute to the disease. Patients would be divided into two groups, statin users and non-users, and followed for years to see which group develops more cancers, but studies like that involve thousands of patients, costs millions of dollars and can take up to a decade. Typically, drug companies make that investment when they're developing a new medication for market, but in this case, statins are already one of the world's best-selling drugs and companies are not talking about funding such expensive studies even if they might show new uses for statins. Epidemiologist Daniel Solomon at Brigham and Women's Hospital in Boston says companies would be taking a risk if a negative side effect showed up.
Dr. DANIEL SOLOMON (Brigham and Women's Hospital): Part of the calculation that a manufacturer makes is understanding what are the possible adverse events that they may run into during such a trial. And when you have a large market for a medicine, such as the statins, there is less impetus to pursue such large new trials.
NEIGHMOND: And that's what happened when Merck Pharmaceuticals ran trials on its painkiller Vioxx to see if it protected against colon cancer.
Dr. SOLOMON: Unfortunately for the manufacturers, the drugs were found to be associated with an increased risk of cardiovascular disease.
NEIGHMOND: Vioxx was taken off the market and Solomon says that's a scenario other drug companies don't want to risk. And there's another reason why companies don't fund these studies, because they can take up to 10 years. Drug patents can expire before the research is conclusive. So the investment could end up creating a market for lower-priced generics instead of adding to the company's profits. And in the case of cancer and statins, right now the federal government is picking up the ball. NCI official Ernie Hawk.
Dr. HAWK: There are two trials. One is looking at the potential statins to block some of the early steps in colon cancer development, and then we also are developing a trial in patients at risk for melanoma.
NEIGHMOND: And if statins show promise in preventing these two cancers, NCI might widen the experiments to see if these cholesterol drugs can also help prevent other types of cancer.
Patricia Neighmond, NPR News.
MONTAGNE: This is NPR News.
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