Statins neither raise nor lower the risk of cancer or cancer mortality, according to a metaanalysis of 26 randomized clinical trials.
Several retrospective studies have suggested that statins reduce the risk of developing cancer by as much as 50%. Some researchers have proposed that the drugs may inhibit carcinogenesis by decreasing systemic inflammation, interfering with neovascular formation, and inhibiting cell proliferation.
However, three metaanalyses have failed to confirm that statins exert a protective effect against cancer, and some investigators have noted that statins have properties that could actually enhance cancer risk, such as inhibiting selenoprotein synthesis and impairing the function of natural killer cells.
To shed light on the issue, Krista M. Dale, Pharm.D., of the University of Connecticut School of Pharmacy, Hartford, and her associates conducted a much larger metaanalysis of 26 randomized clinical trials involving 86,936 subjects. The participants were followed up for 2–10 years for the development of cancer.
The trials included only placebo-controlled or standard-treatment-controlled studies enrolling a minimum of 100 subjects each. Most of these trials assessed the ability of statins to prevent coronary artery disease, but all examined cancer diagnosis or cancer death as a primary or secondary end point.
Statins did not reduce the risk of cancer or of cancer death, Dr. Dale and her associates said (JAMA 2006;295:74–80).
When six major subtypes of cancer—breast, colon, gastrointestinal, prostate, respiratory tract, and skin cancers—were considered individually, statins did not reduce the risk of any of these types.
Similarly, when pravastatin, simvastatin, atorvastatin, cerivastatin, fluvastatin, and lovastatin were considered individually, none of the agents reduced the risk of cancer or cancer death.
And when the metaanalysis was narrowed to assess natural versus synthetic statins and low-lipophilic versus high-lipophilic statins, the results did not change.
“We thought that hydrophilic statins, with their impaired ability to penetrate biological membranes, might provide different effects than lipophilic statins, which readily enter cells, but this was not evident in our study. Similarly, naturally derived statins have a markedly different structure than synthetic statins, but neither type affected the results,” the investigators noted.
“Our results are in agreement with three previous case-control studies that found that statins did not reduce the incidence of cancer,” Dr. Dale and her associates said.