Statin use and survival in patients with gastric cancer in two independent population-based cohorts.

Purpose: Preclinical studies show statins inhibit pathways involved in gastric cancer progression, with observational studies demonstrating reduced gastric cancer risk in statin users. However, few studies have investigated statin use and survival in gastric cancer. We investigated statin use and survival in two large population-based gastric cancer cohorts. Methods: Patients diagnosed with gastric cancer from 1998 to 2012 were identified from English and Scottish cancer registries. Statin prescriptions were identified from linkages to the UK Clinical Practice Research Datalink in England and the Prescribing Information System in Scotland, and deaths identified from national mortality records. Time-dependent Cox regression models were used to calculate hazard ratios (HR) and 95% confidence intervals (CIs) for cancer-specific mortality by statin use in multivariate analysis. Meta-analysis techniques pooled results across the cohorts. Results: The combined cohorts contained 3833 patients with gastric cancer and 2392 cancer-specific deaths. Statin use after diagnosis was associated with reduced cancer-specific mortality (adjusted HR 0.83; 95% CI, 0.74-0.92). HRs for less than 1year and over 1year of statin use were similar (adjusted HR 0.83; 95% CI, 0.73-0.94 and adjusted HR 0.83; 95% CI, 0.64-1.01, respectively). Statin use prior to diagnosis was also associated with reduced cancer-specific mortality (adjusted HR 0.91; 95% CI, 0.84-0.98). Conclusions: In two independent UK cohorts, there was some evidence that statin use was associated with reduced cancer-specific mortality. However, these associations were weak in magnitude and did not follow a clear dose response, and we cannot rule out confounding by stage.