Statins and Cancer

Do statins protect against cancer?

Can statins cause cancer?

The answer to the first question is a qualified "yes" and to the second question is basically "no", according to research studies.

In laboratory conditions, statins certainly exhibit antitumor activities in addition to anti-inflammatory ones. Studies have shown that statins can inhibit malignant cell growth and promote apoptosis (cell death important in stopping cancer.) That doesn't necessarily mean they can help prevent or stop cancer in people, though. This is another incidence of medical research where in vitro and in vivo effects are not identical.

Several large randomized controlled trials of monotherapy for five years show no change in the overall rates of cancer when statins are used regularly. A study of military veterans released in Jan 2008, however, showed that statin use was associated with lower cancer rates in older men. (The participants in the study were mostly men and the average age was over 65.) There is also evidence, although not conclusive, that statins have a chemopreventative effect on melanoma in younger people.

Laboratory tests have shown that statins can slow growth of colon cancer tumors. But those are in laboratory conditions. There is no firm evidence that it works in the body.

As far as actually causing cancer, the average duration of the trials was five years, while patients taking stains would take the drugs for longer periods, probably the rest of their lives. Cancers can occur after long latency periods after the person is exposed to the cause of the disease, so you never really know. As time goes by and we get long term data from the millions of people who use stating drugs, epidemiologists will be able to make an even more sure call on this question.

An article published by M.D. Anderson Cancer Center suggests that statins may lower the risk of cancer just by reducing serum cholesterol levels.

Studies published in May 2008 found that incidences of cancer are dramatically reduced when patients take statins in high doses.

An April 2008 report of Rutgers University research showed that a combination of atorvastatin (Lipitor) and celecoxib (Celebrex) may stop or slow the growth of prostate cancer. This was found in animal models, so scientists aren't ready to say it will work in humans.

Recently (Aug 2007), large scale studies by the Department of Veteran Affairs show statin usage is associated with reduction in rates of lung cancer. And also appear to reduce the risk of pancreatic cancer.

The mechanism for any chemoprevenatitive properties are unknown, but the antioxidant properties may provide a clue. Oxidative stress inside the body contributes to growth of plaques in the blood vessel. Oxidative stress is also bad for the heart. Like the phytochemicals in fruits and vegetables, statins are "antioxidants" - they react with the oxidizing agents so those agents don't damage cells. Just as statins are competitive inhibitors of HMG-CoA reductase in the liver (to slow the production of cholesterol), so they compete for oxidating agents. And by reducing the circulation of oxidized LDLs, statins inhibit the uptake of LDLs by macrophages.

Statins inhibit oxidant enzymes like reduced nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase and myeloperoxidase. They reduce endothelial dysfunction mainly by their ability to enhance endothelial nitric oxide bioavailability, which is achieved by several mechanisms. The antioxidant properties of statins extend to organ protection especially the myocardium and the lungs.

Other news:

Mayo Clinic Study on chemoprevention of colorectal and lung cancers

Study shows statin use does not cut risk of colorectal cancer

Statins and memory

Evidence that statins prevent age-related macular degeneration.

A study finds that statin use is correlated with an increase in cancer risk. However, the risk is very small and some scientists are skeptical, especially as this contradicts previous studies.

Mayo Clinic on clinical study of chemoprevention including atorvastatin.