Statin uses and mortality in colorectal cancer patients: An updated systematic review and meta‐analysis

BACKGROUND: Colorectal cancer (CRC) remains one of the most common types of cancer and a leading cause of death worldwide. Previous studies indicated that statins may have a potential protective effect on CRC. METHODS: We conducted this meta‐analysis to systematically assess the overall and cancer‐specific survival benefit of statin uses on CRC patients. Related references were identified through PubMed, the Cochrane Library, Web of Science, EMBASE, and SCOPUS from inception to August 2017. Adjusted hazard ratios (HRs) were adopted to calculate summary hazard ratios (HRs) with 95% confidence intervals (95% CIs), using a random‐effects model. RESULTS: Total fourteen studies involving 130 994 patients were included in this meta‐analysis. Six studies reported the association between pre‐diagnosis statin uses and CRC mortality, while 11 studies investigated mortality in patients using statins after CRC diagnosis. For pre‐diagnosis statin uses, the pooled HR of all‐cause mortality (ACM) was 0.85 (95% CI, 0.79‐0.92) and the pooled HR of cancer‐specific mortality (CSM) was 0.82 (95% CI, 0.79‐0.86). In terms of post‐diagnosis statin uses, the pooled HR of ACM was 0.86 (95% CI, 0.76‐0.98), and the pooled HR of CSM was 0.79 (95% CI, 0.70‐0.89). For post‐diagnosis statin uses, there is no difference in ACM when stratified by KRAS gene (KRAS) mutation status. Results of ACM and CSM did not markedly alter in other subgroup analyses. CONCLUSION: Our meta‐analysis demonstrates that both pre‐diagnosis and post‐diagnosis statin uses are associated with reduced ACM and CSM for CRC patients.