Screening for Helicobacter pylori to Prevent Gastric Cancer

To the Editor In a recent trial, there were no differences in gastric cancer incidence or mortality between the 2 treatment groups at a median follow-up of 5.7 years (IQR, 4.9-6.5 years). The progression time from early asymptomatic to symptomatic gastric cancer is unknown and may be longer than the follow-up time of the trial. Presentation of cumulative incidence curves would be helpful to further gauge the effect of the intervention. Furthermore, the study excluded 4 patients with gastric cancer diagnosed on endoscopy after trial entry. While H pylori eradication may not have affected the development of cancer in these patients, excluding them creates bias because the control group was not exposed to gastroscopy with early detection of prevalent cancers. We suggest a recalculation of screening effects including the 4 patients who were excluded. Additionally, we are interested to know if more than 1 H pylori stool test was offered (for example, with subsequent FIT), which would provide information about reinfection and subsequent cancer risk.