TUESDAY, Jan. 3, 2006 (HealthDay News) -- Hopes that the cholesterol-lowering drugs known as statins might reduce the risk of colorectal cancer have been dashed by the results of two major new studies.
One looked at 27 trials of statins for cardiovascular disease for a total of nearly 87,000 participants, and found no reduced incidence of colorectal cancers and a variety of other cancers in people who took the drugs when compared with those who didn't.
The other also found no reduced incidence for those who took statins in the 132,136-strong Cancer Prevention Study II Nutritional Cohort.
Expectations had been raised by previous studies, one of which found a 47 percent reduction in cancers of the colon and rectum for people who took statins for more than five years.
But those studies "had a lot of methodological flaws," said C. Michael White, a professor of pharmacology at the University of Connecticut. His analysis of the 27 trials appears in the Jan. 4 issue of the Journal of the American Medical Association.
"In our study we did a meta-analysis of all the trials, and were not able to show any reduction in cancer or in cancer deaths," White said.
Most of the people in those trials were taking a single drug, pravastatin (Pravachol), "but when we looked at other statins, we couldn't come up with a mixture that suggested there might be a protective effect," he said.
The second study, led by Eric J. Jacobs, an epidemiologist with the American Cancer Society, appears in the Jan. 4 issue of the Journal of the National Cancer Institute. Again, their finding was negative: "Our results do not support the hypothesis that statins, as a class of drugs, strongly reduce risk of colorectal cancer," they wrote.
The two studies are "consistent and complementary," Jacobs said. "They are consistent in that both show no effect on colon cancer risk. They are complementary in that the meta-analysis was able to look at varieties of statins, whereas our study was able to look at longer-term use."
The news isn't as bad as it might seem, White said.
"The good news is that when statins first came out, people were worried that they might cause cancer," he said. "Now we know the effect is pretty neutral."
And the reports provide no reason to stop taking statins, White said. "They still do miraculous things for people with heart disease," he said. "Just don't take them to reduce the risk of cancer. There are other things to do, like not smoking and improvements in diet."
An essential step for men and women over 50 is to talk to a doctor about a colon cancer screening test to detect polyps that can be removed before they become cancerous, Jacobs said.
The studies don't totally disprove the notion that statins might protect against cancer, said Dr. Donald A. Smith, director of lipids and metabolism at Mount Sinai Medical Center in New York City.
"But it is going to be a very mild effect, and it certainly won't occur in the first five years," he said. "The long-term question is whether it has any effect at all."
More information
Colorectal cancer and the steps you can take to avoid it are described by the National Cancer Institute.
