Statins and cancer: A systematic review and meta-analysis

Background: Systematic reviews on the association between statin therapy and cancer have focused on randomised trials without assessing the quality of evidence. We aimed to review the overall evidence taking study quality into consideration. Methods: Publications of original studies on the effect of statin treatment on cancer in adult patients were searched on MEDLINE, EMBASE and CENTRAL databases upto October 2007. Our search yielded 37 eligible original studies out of 3607 references. Five studies were additionally found through manual search. Thus, 42 studies were included in the analyses: 17 randomised controlled trials, 10 cohort studies, and 15 case-control studies. Findings: Statins had no effect on the overall incidence of cancer (median risk ratio (RR) 0.96, range 0.72 to 1.2), or on the incidence of lung (median RR 0.92, range 0.83 to 3.0), breast (median RR 1.04, range 0.74 to 19) or prostate cancer (median RR 0.96, range 0.33 to 1.7). They seemed to protect from stomach (median RR 0.59, range 0.40 to 0.88) and liver cancer (median RR 0.62, range 0.33 to 1.2), and from lymphoma (median RR 0.74, range 0.28 to 2.2). They increased the incidence of both melanoma (median RR 1.5, range 1.3 to 1.7) and non-melanoma skin cancer (median RR 1.6, range 1.2 to 2.2). The effect varied, yet inconsistently, by statin type. The median follow-up time was 4 years. The strength of evidence was mostly weak. Interpretation: The evidence suggests that statins do not have short-term effects on cancer risk. The evidence on potentially protective or harmful effects is inconclusive. High quality cohort studies with long follow-up are needed to resolve the issue. (c) 2008 Elsevier Ltd. All rights reserved.