Statin use and risk of gastrointestinal cancer: a meta-analysis of cohort studies

Objective: To evaluate the effect of statins on esophageal cancer, pancreatic cancer, gastric cancer, colon cancer and rectal cancer risk. Methods: Relevant studies were identified by searching MEDLINE, EMBASE, and PUBMED up to Feb 2017. We estimated RR (relative risk) with 95% confidence interval (CI) and subgroup analysis also be conducted. In addition, we estimated RR ratios (RRRs) between men and women. Results: Seventeen cohort studies were included for the meta-analysis. The pooled results showed that statin use could decrease the risk of esophageal cancer, especially for the long-term user (All: RR = 0.72, 95% CI = 0.49-0.96; Long-term use: RR = 0.65, 95% CI = 0.36-0.93). Women had a borderline significant 16% increased risk for esophageal cancer conferred by statin use compared with men (RRR = 0.84, 95% CI = 0.60-1.08). Statin user yielded a decreased risk of gastric cancer (RR = 0.74, 95% CI = 0.56-0.92). The subgroup analyses based on race showed that statin use conferred a significant protective effect on the gastric cancer in Asian population, but not in Western population. Our results did detect significant association of statin use with pancreatic cancer in Asian population, but not in all populations (Asian population: RR = 0.55, 95% CI = 0.48-0.63; All populations: RR = 0.79, 95% CI = 0.51-1.07). Compared with non-users, statin users had a borderline significant 12% decreased risk for rectal cancer (RR = 0.87, 95% CI = 0.74-1.01). The pooled analysis did not detect the significant association of satin use with colon cancer risk (RR = 0.98, 95% CI = 0.92-1.03). Conclusion: Statin use may decrease the risk of esophageal cancer, gastric cancer, pancreatic and rectal cancer. Further well-designed large studies with prospective cohort design are necessary to draw definitive conclusions.