What is Statin? Can It Really Reduce the Risk of Cancer?

Statin is a class of drug used to lower cholesterol levels to prevent cardiovascular diseases in people with high level of LDL cholesterol and total cholesterol. Statin has been around since the 1980s and several clinical trials have demonstrated the effects of statin on lowering cardiovascular diseases.

In recent years, several studies reported that statin also has preventive effects on cancers. So maybe this old drug still has some tricks up its sleeve.

Most notably, statin is believed to lower the risk of colorectal cancer. However the evidences seem to contradict each other. Poynter et al (2005) reported a 47% reduction in risk of colorectal cancer in patients using statin more than 5 years.On the other hand, Shepherd et al. (2002) reported that in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) trial, which included more elderly patients, participants using pravastatin had a 46% increased risk of gastrointestinal cancer. Similarly, Vinogradova et al.(2007) examined colorectal cancer cases in 454 general practices in the United Kingdom between 1995 and 2005. They then matched this population with a control population. They conclude that prolonged use of nonsteroidal anti-inflammatory drug and cyclooxygenase-2 inhibitor was associated with a reduced colorectal cancer risk. However, prolonged use of statin was not associated with a reduced colorectal cancer risk.

Bonovas et al (2007) performed a meta-analysis of 18 studies, in which colorectal cancers are reported as secondary endpoints. These studies involved a total of 1.5 million participants. They found that there was no evidence to support the link betewen statin use and reduced risk of colorectal cancer either among RCTs or among cohort studies. In case-control studies, statin use leads to a 10% reduction in colorectal cancer risk. Bonovas et al. (2007) concluded that the evidences do not support the hypothesis that statin strongly reduce the risk of colorectal cancer.

Pocobelli et al. (2008) conducted a similar study on the effects of statin on breast cancer. They examined a population of women aged 50 years and older in three U.S. states, namely Wisconsin, Massachusetts and New Hampshire. Pocobelli et al. (2008) interviewed patients diagnosed with cancer from 1995-2001 and were compared with a control population. Only use of fluvastatin leads to a 50% decreased risk of breast cancer (95% confidence interval, 30%-80%). Interestingly, the reduction does not depend on the duration of using fluvastatin. Other statins, such as simvastatin, lovastatin, and pravastatin are not associated with an increased risk of breast cancer.

Khurana et al (2002) analyzed data on 483,733 patients from eight states south central United States to quantify the effects of statin on lung cancer. They found that statin use more than 6 months was associated with a risk reduction of lung cancer of 55%. However, more studies are needed to confirm the effect of statin on lung cancer.

Overall, statin might reduce the risk of cancer but the effects are not strong.

Sources:

Poynter, S.B. Gruber, P.D.R. Higgins, R. Almog, J.D. Bonner, H.S. Rennert, M. Low, J.K. Greenson and G. Rennert, Statins and risk of colorectal cancer, N Engl J Med 352 (2005), pp. 2184–2192

J. Shepherd, G. Blauw, M. Murphy, E. Bollen, B. Buckley, S. Cobbe, I. Ford, A. Gaw, M. Hyland, J.W. Jukema, A.M. Kamper, P.W. Macfarlane, A.E. Meinders, J. Norrie, C.J. Packard, I.J. Perry, D.J. Stott, B.J. Sweeney, C. Twomey, R.G. Westendorp and PROSPER study group, PROspective Study of Pravastatin in the Elderly at Risk Pravastatin in elderly individuals at risk of vascular disease (PROSPER): a randomised controlled trial, Lancet 360 (2002), pp. 1623–1630.

Vinogradova Y. Risk of colorectal cancer in patients prescribed statins, nonsteroidal anti-inflammatory drugs, and cyclooxygenase-2 inhibitors: nested case-control study. Gastroenterology. 2007 Aug;133(2):393-402.

Bonovas S. Statins and the risk of colorectal cancer: a meta-analysis of 18 studies involving more than 1.5 million patients. J Clin Oncol. 2007 Aug 10;25(23):3462-8.

Khurana V. Statins reduce the risk of lung cancer in humans: a large case-control study of US veterans. Chest. 2007 May;131(5):1282-8. PMID: 17494779 [PubMed - indexed for MEDLINE]