Background : Adenocarcinoma of the esophagus (EAC) was previously a rare tumor, however in recent decades the incidence has risen faster than all other cancers in developed countries including Australia. It has been suggested that people who regularly use nonsteroidal anti-inflammatory drugs (NSAIDs) may experience lower rates of epithelial cancers of the gastrointestinal tract, including EAC. We sought to test this hypothesis in a population-based case control study. Patients and methods : Case participants were 788 patients diagnosed with histologically confirmed EAC between July 1, 2002 and June 30, 2005 who were identified from hospitals around Australia. Controls (1578) were sampled randomly from Australian Electoral Roll (a compulsory population register), frequency matched to the cases by sex, age group and state of residence. Information on salient exposures (including smoking, alcohol, diet, weight, height and medical history) was collected through self-completed postal questionnaires. A follow-up telephone interview was conducted to obtain detailed information on NSAID consumption. Estimates of risk (odds ratios [ORs] and corresponding 95% confidence intervals [CIs] were calculated for the association between intake of NSAIDs during the life time and EAC in different categories and was adjusted for related confounding factors including age, gender, education, history of reflux, body mass index (BMI), smoking and alcohol. Results : Risk of EAC was associated with a frequent past history of acid reflux 10 years ago (OR 5.01, 95% CI 3.25-7.9), more than 30 pack year smoking history (OR 2.31, 95% CI 1.76-3.04), and obesity (maximum BMI > 30 kg/m2) (OR 2.82, 95% CI 1.87-4.26). After adjusting for all of these factors in a multivariate model, we observed significantly lower risks of EAC among ever users of NSAIDs compared with never users (OR 0.51, 95% CI 0.41-0.62). When evaluated according to regularity of intake, we found a slight risk reduction among regular users than occasional users (regular users OR 0.47, 95%CI 0.33-0.57; occasional users OR 0.59, 95% CI 0.45-0.76). We also found lower risks associated with recent NSAID use (last 1-10 years OR 0.49, 95% CI 0.39-0.61) than past use (>10 years ago OR 0.64, 95% CI 0.41-1.00). Conclusion : Our findings suggest that use of NSAIDs reduces the risk of EAC, after accounting for the effects of other confounding factors. Regular use of NSAIDs, and recent use, appeared to cause lower risks of EAC than occasional or historic use of these medications.
[Fifth AACR International Conference on Frontiers in Cancer Prevention Research, Nov 12-15, 2006]