Non-steroidal anti-inflammatory drug use and the risk of gastric cancer: a systematic review and meta-analysis

Background: The relationship between the use of non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, and the risk of gastric cancer has not been well studied. We performed a systematic review and meta-analysis of published studies to evaluate the association between use of this class of drugs and the risk of gastric cancer. Methods: A fully recursive literature search to January 2003 was conducted in MEDLINE, PubMed, and CANCERLIT to identify potentially relevant case-control or cohort studies. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated under a random-effects model. Results: Nine studies (eight case--control and one cohort) with a total of 2831 gastric cancer case patients were identified. NSAID use was associated with a reduced risk of gastric cancer, with a summary odds ratio of 0.78 (95% CI = 0.69 to 0.87). Users of aspirin (OR = 0.73, 95% CI = 0.63 to 0.86) and non-aspirin NSAIDs (OR = 0.74, 95% CI = 0.55 to 1.00) experienced similar magnitudes of risk reduction. Regular users of NSAIDs (OR = 0.57, 95% CI = 0.44 to 0.74) experienced a lower risk of gastric cancer relative to nonusers than did irregular users (OR = 0.76, 95% CI = 0.62 to 0.94; P = .09 versus regular users). A stratified analysis showed that NSAID use was associated with a statistically significant reduction in risk of noncardia gastric cancer (OR = 0.72, 95% CI = 0.58 to 0.89), but not of gastric cancer at the cardia (OR = 0.80, 95% CI = 0.53 to 1.20). There was no evidence that study design or type of control subject substantially influenced the estimate of effects. Conclusion: NSAID use was associated with a decreased risk of gastric cancer in a dose-dependent manner. This finding warrants proper clinical trials in populations with high risk of gastric cancer.