Low-Dose Aspirin Use Does Not Increase Survival in 2 Independent Population-Based Cohorts of Patients With Esophageal or Gastric Cancer

Abstract

Preclinical studies have shown aspirin to have anticancer properties and epidemiologic studies have associated aspirin use with longer survival times of patients with cancer. We studied 2 large cohorts to determine the association between aspirin use and cancer-specific mortality in patients with esophageal or gastric cancer. We performed a population-based study using cohorts of patients newly diagnosed with esophageal or gastric cancer, identified from cancer registries in England from 1998 through 2012 and the Scottish Cancer Registry from 2009 through 2012. Low-dose aspirin prescriptions were identified from linkages to the United Kingdom Clinical Research Practice Datalink in England and the Prescribing Information System in Scotland. Deaths were identified from linkage to national mortality records, with follow-up until September 2015 in England and January 2015 in Scotland. Time-dependent Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer-specific mortality by low-dose aspirin use after adjusting for potential confounders. Meta-analysis was used to pool results across the 2 cohorts. The combined English and Scottish cohorts contained 4654 patients with esophageal cancer and 3833 patients with gastric cancer, including 3240 and 2392 cancer-specific deaths, respectively. The proportions surviving 1 year, based on cancer-specific mortality, were similar in aspirin users vs non-users after diagnosis with esophageal cancer (48% vs 50% in England and 49% vs 46% in Scotland, respectively) or gastric cancer (58% vs 57% in England and 59% vs 55% in Scotland, respectively). There was no association between postdiagnosis use of low-dose aspirin and cancer-specific mortality among patients with esophageal cancer (pooled adjusted HR, 0.98; 95% CI, 0.89-1.09) or gastric cancer (pooled adjusted HR, 0.96; 95% CI, 0.85-1.08). Long-term aspirin use was not associated with cancer-specific mortality after diagnosis of esophageal cancer (pooled adjusted HR, 1.03; 95% CI, 0.85-1.25) or gastric cancer (pooled adjusted HR, 1.06; 95% CI, 0.85-1.32). In analyses of 2 large independent cohorts in the United Kingdom, low-dose aspirin usage was not associated with increased survival of patients diagnosed with esophageal or gastric cancer.