By Dr Sharan Sharma

Regular nonsteroidal anti-inflammatory drug (NSAID) use can be a feasible way to prevent cancer in Helicobacter pylori infected gastric ulcer patients according to a new study that was published in June 20 issue of Journal of Clinical Oncology. Researchers from Taiwan did a nationwide retrospective cohort study using data from National Health Insurance database. They took 52,161 hospitalized peptic ulcer patients and divided them into regular NSAID users and non-NSAID users.

Gastric cancer is the fourth most common cancer and is the second most common cause of cancer mortality. Aspirin and other NSAIDs use have been found to have beneficial effects in preventing gastric cancer in some of the previous studies. Aspirin and NSAIDs have been suggested to prevent gastric cancer by inhibiting production of cyclooxygenase (COX) -1 and COX-2 through both prostaglandin-dependent and -independent pathways. However, these studies did not provide definitive answers to the type of the interaction between NSAID use and H pylori infection, the subpopulation for which benefits of chemoprevention outweigh the risks gastrointestinal bleeding, and the number needed to treat (NNT) remain unclear.

Among 52,161 cases who were admitted with the primary diagnosis of gastric ulcer 27,016 were selected into non-NSAID user and 25,145 were defined as regular NSAID user and they were followed up for 5.17 and 5.88 years respectively.

Patients with peptic ulcers who did not use NSAIDs had significantly higher risk of gastric cancer compared with the general population (Standardised Incidence ratios (SIR), 2.11; 95% CI, 2.07 to 2.15), but those with regular NSAID use showed significantly lower risk of gastric cancer compared with the general population (SIR, 0.79; 95% CI, 0.77 to 0.81). On stratified analysis, non-NSAID users had significantly higher risks of gastric cancer in nearly all stratified groups compared with the general population. In contrast, regular NSAID users were associated with reduced risk of gastric cancer for all stratified groups compared with the general population except for patients of female sex, with gastric ulcer and non-H pylori-associated gastric ulcer.

However, the authors caution against extrapolating their results as they see a few limitations in their study. They say "Our results were based on hospitalised patients with peptic ulcer diseases so selection bias might have occurred". "The other thing is although we have conducted a multivariate analysis to examine whether NSAID use is an independent protective factor, many other factors are not available for adjustment, such as precancerous lesions and environmental factors, and so on" they add.