S0417 Benefits of Aspirin as Chemoprevention for Esophageal Squamous Cell Carcinoma and Adenocarcinoma

Abstract

INTRODUCTION: Esophageal cancer (EC) is among the ten most common cancers in the United States. Adenocarcinoma (EAC) and squamous cell cancer (SCC) make up 90% of all malignant esophageal tumors. Tobacco and alcohol consumption have been recognized as major risk factors for SCC, while Barrett’s esophagus and gastro-esophageal reflux are associated with an increased risk of progression to EAC. While attempting to control these triggers, the incidence of SCC has steadily decreased over the last decade; however, the incidence of EAC has continued to rise. The aim of this meta-analysis is to evaluate the potential benefits of aspirin as a chemoprotective agent against esophageal cancer. METHODS: We performed an electronic search of PUBMED databases for studies that reported data on EC occurrences (all EC, EAC and ESCC) and aspirin use from inception to January 1, 2020. Case reports, case series, editorials and review articles were excluded. Primary outcome included pooled odds of all EC occurrence in persons who were on aspirin compared to those who were not. Secondary outcomes included the pooled odds of EAC and ESCC occurrence in persons who were on aspirin compared to those not taking it. We also performed a meta-regression for the cancer incidence (all EC, EAC and ESCC) based on duration of follow-up. Meta-analysis outcomes, heterogeneity (I2), meta-regression (for effect of covariates) were derived by statistical software R and open meta-analyst. RESULTS: A total of 11 studies with 34,779 patients with a mean age of 62.3 ± 5.6 years and a mean follow-up duration of 116 months (range 24-264 months) were included for analysis. There were 6 studies that reported data on incidence of overall EC, 7 studies reporting incidence of EAC and 4 studies reporting incidence of ESCC in patients who were on aspirin. Odds of EC were significantly lower in individuals who were taking aspirin compared to those who were not (OR 0.54; 95% CI 0.33–0.88; I2 = 82%). We also noted significantly lower odds of both EAC (OR 0.60; 95% CI 0.44–0.82; I2 = 69%) and ESCC (OR 0.59; 95% CI 0.46–0.78; I2 = 79%) in patients who were taking aspirin compared to those who were not. Meta-regression did not demonstrate any significance of duration of follow-up to the incidence of all EC (P = 0.38), EAC (P = 0.29) or ESCC (P = 0.45). We did not assess for publication bias since there were fewer than 10 studies in all outcome evaluations. CONCLUSION: The use of daily aspirin was associated with decreased incidence of all EC, EAC and ESCC.