Can statins reduce risk of lung cancer, especially among elderly people? A meta-analysis.

OBJECTIVE As the most common cause of cancer mortality throughout the world, lung cancer has drawn people's attention on how to reduce the risk with chemopreventive ways. Many epidemiological studies have shown inconsistent effects of statins on lung cancer, but some observational studies have showed that statins had protective effect on lung cancer among elderly people. So we preformed this meta-analysis to find whether statins were chemopreventive. METHODS We searched MEDLINE, EMBASE and Web of Science databases from inception to September, 2013. A total of 23 studies were selected, including 15 observational studies and 8 randomized controlled trials (RCTs). Both fixed and random-effects models were used to calculate pooled estimates in primary and sensitivity analyses. We used Q and I(2) statistics to assess statistical heterogeneity, and evaluated publication bias by Begg's test and Egger's test. RESULTS No association between statins and lung cancer risk was identified either in the meta-analysis among RCTs [relative risk (RR): 0.95, 95% confidence interval (95% CI): 0.85-1.06] or observational studies (RR: 0.89, 95% CI: 0.77-1.04). We also selected 6 observational studies that all researched on elderly people. The result of meta-analysis showed that there was still no protective effect between statins and lung cancer among elderly people (RR: 1.03, 95% CI: 0.96-1.11). CONCLUSIONS Our results did not support a protective effect of statins on the overall lung cancer risk and the lung cancer risk among elderly people. More well-designed RCTs are needed to enhance our understanding of the chemopreventive effect of statins on lung cancer.