January 10, 2008
American Cancer Society

Could Statins Prevent Cancer?

According to a study published this week in the Journal of the National Cancer Institute, statin users are less likely to develop cancer compared to those who don't take the cholesterol-lowering drugs. Experts caution, however, that this single study is not strong enough to be considered evidence of the drug's preventive properties.

"While statins remain important drugs for the prevention of heart disease, they should not be used in the hopes of preventing cancer," said Eric Jacobs, PhD, strategic director, pharmacoepidemiology, at the American Cancer Society.

Why It's Important: We know certain behaviors affect an individual's risk of developing cancer. Tobacco use accounts for nearly one-third of cancer deaths in the US, while eating a diet rich in fruits and vegetables has been shown to help reduce cancer risk. Despite all evidence, however, many people struggle with adopting healthier lifestyles. Although statin use can have side effects (including potentially serious liver damage and muscle problems), if these drugs were found to prevent cancer, they might provide patients with a relatively easy and safe way to reduce their cancer risk.

What's Already Known: Statins, such as atorvastatin (Lipitor) and simvastatin (Zocor), are some of the most commonly prescribed drugs for lowering the risk of heart disease. They work by blocking an enzyme responsible for making artery-clogging cholesterol. The results of lab studies have shown that statins interfere with cancer cell growth, but researchers have been unable to clearly show that the drugs reduce cancer risk in people.

"Randomized trials have definitively shown that using statins does not reduce cancer risk, at least in the short-term, and most previous observational studies have not found clear evidence that even long-term statin use can protect against cancer," said Jacobs.

The researchers who led this study argue that previous studies were not designed to specifically address cancer risk, and that in most of these trials, the study population was too young (the mean age of participants was under 65), and that follow-up periods (often less than 5 years) may have been too short, to adequately detect the impact of statin use.

How This Study Was Done: The researchers, who included doctors at the VA Boston Healthcare System, Brigham and Women's Hospital, Harvard Medical School, and Boston University School of Medicine, studied the records of patients with high blood pressure who were enrolled in the Veterans Affairs New England Healthcare System between January 1, 1997 and December 31, 2005. They screened for smoking history, other illnesses such as diabetes or thyroid disease, age, weight, aspirin use, and history of colon cancer screening with colonoscopy and sigmoidoscopy. They then analyzed cancer incidence rates among statin and non-statin users. The average age of participants was 67, with 5 years as the average follow-up time.

What Was Found: Among 37,248 patients who were taking a statin, 9.4% developed cancer, compared to 13.2% of the 25,594 patients who weren't taking one of these drugs. Researchers found an especially high correlation with statin use and reduced risk for lung and colorectal cancers, as well as melanoma.

These results don't tell the whole story, however. Researchers only had electronic records to go by, and in many cases, those records failed to give a comprehensive view of a patient's well-being. For example, the smoking history of many of the participants was unknown (researchers didn't have data for 56% in the statin group and 63% in the non-statin group). Because smoking is a significant risk factor for multiple cancers, and especially for lung cancer, not having that information for so many study participants may have skewed results. Further, while researchers screened for aspirin use, which is thought to play a role in reducing colorectal cancer risk, their data was based on whether an individual had a prescription, which can't account for those who regularly buy it over the counter.

The authors of the study also note that the number of cancer cases might be lower among statin users because they may have received more counseling regarding healthy lifestyle choices and the importance of cancer screening.

The Bottom Line: While this study is far from conclusive, it does reflect the need for more study into the possible preventative properties of statins.

Still, these drugs are not recommended for reducing cancer risk at this time. For now, the best way to reduce your cancer risk is to avoid tobacco, follow ACS's nutrition and activity guidelines, and schedule regular screening appointments.