WASHINGTON, Jan. 3 (UPI) -- Two independent studies have found that the cholesterol-lowering class of drugs called statins does not reduce the risk of cancer, casting doubt on previous studies suggesting the drugs could ward off the disease.
The first study, a meta-analysis that appears in the Jan. 4 issue of the Journal of the American Medical Association, found no reduction in the incidence of cancer or cancer deaths among statin users.
The second study, which appears in the Jan. 4 issue of the Journal of the National Cancer Institute, found that patients taking statins for five or more years developed colorectal cancer at the same rate as those who had never used the medications.
"Statins have a neutral effect on cancer and cancer death risks in randomized controlled trials," C. Michael White, of the University of Connecticut and Hartford Hospital in Hartford, Conn., and colleagues wrote in JAMA. "We could find no type of cancer that statins benefited or subtype of statin that reduced the risk of cancer," the researchers added.
The findings will probably have minimal effect on drug stocks, as the biggest threat to statin manufacturers is patent expirations. Bristol-Myers Squibb's Pravachol, which raked in $2.6 billion in sales in 2004, goes off patent this year. The patent on Merck's Zocor, which generated $5.2 billion in sales in 2004 and about $4.5 billion in 2005, also expires this year.
In the JAMA study, White's team included in their analysis 27 randomized controlled trials of statins conducted between 1966 and July 2005 that involved nearly 87,000 participants.
"No reductions were noted for cancers of the breast, colon, gastrointestinal tract, prostate, respiratory tract, or skin (melanoma) when statins were used," the researchers wrote. They noted Zocor and Pravachol were the two statins predominantly used in the trials they analyzed, but even when they evaluated these two drugs separately, there was still no impact on cancer incidence or death.
In the second study, conducted by the American Cancer Society, researchers examined data from ACS' Cancer Prevention Study II Nutrition Cohort, which involves more than 132,000 participants.
Approximately 815 cases of colorectal cancer were identified among this group, but there was no reduction in risk among patients on the drugs for five or more years compared to those who had never been on the medications.
These results stand in sharp contrast to an epidemiological study conducted by Israeli researchers reported in May in the New England Journal of Medicine, which indicated statins may cut the risk of colorectal cancer by nearly 50 percent.
"Our results are similar to those of several smaller, prospective studies but very different from the dramatic drop in risk seen in the recent case control study from Israel," said Eric Jacobs, lead author of the study and senior epidemiologist with the American Cancer Society.
"Based on current evidence, statins, while valuable and effective drugs for preventing heart disease, should not be used in the hopes of preventing colorectal cancer," Jacobs added.
Charles Fuchs, a medical oncologist with the Dana-Farber Cancer Institute who was not involved in the studies, told United Press International the JAMA study suggests statins do not lower cancer risk, but added that the finding is not definitive because its based on a meta-analysis.
"Ultimately, I believe more research is needed," Fuchs said.
