Long Term Statin Use Not Linked To Cancer

Statin use has increased dramatically in the United States over the past two decades. In 1990 just 2% of adults over 45 were taking statins to control cholesterol compared to 25% in 2010. Statins are among the most commonly prescribed drugs and are a huge source of revenue for the pharmaceutical industry. While there is no doubt that statins have had a tremendous impact on reducing the prevalence of hypercholesterolemia (high cholesterol), concerns have been raised about whether long term statin use might increase the risk of cancer. Fortunately, the majority of studies looking at this issue have found either no link, or a small decrease in the risk of cancer amongst statin users.

One of the largest studies on statin use and cancer was conducted in 2008 and involved the study of more than 60,000 American veterans who were followed up for an average of 5 years. Over the follow up period, 13.2% of non-statin users developed cancer compared to just 9.4% of statin users. After adjusting for potential confounders, statin use was associated with a 26% reduction in the risk of cancer. Lung and colorectal cancer were the cancer types showing the largest decrease in risk with a 30% and 35% reduction respectively. The researchers also observed a dose-response relationship with those in the highest tertile for statin use showing the greatest decrease in cancer risk.

A case control study involving 20,000 Danish residents found a 20% reduction in overall cancer risk in statin users. Those who had used statins for at least 4 years experienced an impressive 36% reducion in risk.

Finally, an extensive meta-analysis of 35 previous statin trials was conducted in 2006 by researchers at the University of Athens. 23 trials reported a lower risk of cancer in statin users, 10 reported an increased risk, while the remaining 2 found no association. The researchers calculated an overall cancer RR of 0.99 for statin use and concluded that statin use appeared to be unrelated to cancer risk.

Statins may reduce cancer risk through reducing levels of inflammation in the body. A 2001 study, published in the Journal of the American Medical Association, found a 16.9% reduction in c-reactive protein ( a marker of inflammation) following 24 weeks of statin therapy compared to a placebo. Molecular studies have also shows that statins induce apoptosis (cell suicide) in both cancerous breast and colon cancer cells.

While any reduction in risk from statin use is likely to be small, it is at least comforting to see no evidence of a positive association between statins and cancer. One area of concern is that the majority of studies conducted to date have had a relatively short follow up time. Given the increase in the number of middle aged statin users, many of which will continue to use them for life, it would be reassuring to see some studies with longer follow-up times, ideally in excess of 20 years.