CHICAGO -- Two new studies deal a double blow to hopes that cholesterol-lowering statin drugs could help prevent cancer as well as heart disease.
In one report, researchers analyzed 26 rigorous, randomized studies involving more than 73,000 patients, and concluded that drugs such as top-selling Lipitor and Zocor had no effect on the risk of developing or dying from any form of cancer.
The findings appear in today's Journal of the American Medical Association. The other study, published in the Journal of the National Cancer Institute, found that cholesterol-lowering drugs, including statins, were of no benefit for preventing colorectal cancer.
''We were very hopeful that we would verify there was an anticancer effect," said C. Michael White of the University of Connecticut School of Pharmacy, who led the analysis appearing in the journal. ''We ended up showing no change in cancer or cancer death."
White said the new findings -- as well as the rare but potential side effects of statins, which can include liver damage and muscle pain -- should discourage doctors from prescribing them solely to prevent cancer.
People should continue taking them to lower cholesterol and prevent heart attacks, he said. ''It really is a great drug for heart disease."
Hope for statins as cancer fighters was sharpened by the fact that so many people already take them to lower cholesterol and the drugs are widely considered safe. Previous research, including animal studies and observational studies of people, had suggested statins might prevent various types of cancer.
For example, researchers looked at medical records for 1.4 million patients treated at 10 Veterans Affairs medical centers and found that those taking statins had lower rates of breast, prostate, and lung cancer than those who hadn't taken such drugs.
And a study of Israeli patients published last year showed a 47 percent lower risk of colorectal cancer in people who used statins for at least five years. Patients were not randomly picked. Researchers believe randomized studies yield the best evidence.
Dr. Stephen Gruber of the University of Michigan, who led the Israeli study, said, that the new analysis is valuable but suggests that more research is needed. ''When you see contrasting conclusions like this, it's often an opportunity to learn more," Gruber said.