A pragmatic randomized clinical trial conducted in Taiwan has found that screening for Helicobacter pylori (H. pylori) in conjunction with fecal immunochemical testing (FIT) did not significantly reduce the incidence or mortality of gastric cancer compared to FIT screening alone. The study, involving over 152,000 participants, raises questions about the effectiveness of widespread H. pylori screening as a primary prevention strategy for gastric cancer.
The trial, published in JAMA, randomized residents aged 50 to 69 years eligible for biennial FIT screening to either an invitation for H. pylori stool antigen (HPSA) testing plus FIT or FIT alone. The primary outcomes were gastric cancer incidence and gastric cancer mortality. While the study did not demonstrate a statistically significant reduction in either outcome, post-hoc analyses adjusting for differences in screening participation and follow-up suggested a potential benefit in reducing gastric cancer incidence.
Key Findings and Participation Rates
The gastric cancer incidence rates were 0.032% in the HPSA+FIT group and 0.037% in the FIT-alone group (mean difference, -0.005%; 95% CI, -0.013% to 0.003%; P = .23). Gastric cancer mortality rates were 0.015% in the HPSA+FIT group and 0.013% in the FIT-alone group (mean difference, 0.002%; 95% CI, -0.004% to 0.007%; P = .57).
Notably, screening participation rates differed significantly between the two groups, with 49.6% participation in the HPSA+FIT group and 35.7% in the FIT-alone group. This difference in participation may have influenced the study's overall results. Among participants with positive HPSA results, 71.4% received antibiotic treatment, with a high eradication rate of 91.9%.
Post-Hoc Analysis and Implications
After adjusting for differences in screening participation, length of follow-up, and patient characteristics in post hoc analyses, an invitation for HPSA+FIT was associated with lower rates of gastric cancer (0.79 [95% CI, 0.63-0.98]) but not with gastric cancer mortality (1.02 [95% CI, 0.73-1.40]), compared with FIT alone.
The study's authors conclude that while an invitation to test for HPSA combined with FIT did not reduce rates of gastric cancer or gastric cancer mortality compared with FIT alone, the post-hoc analyses suggest a potential benefit in reducing gastric cancer incidence when accounting for differences in screening participation and follow-up.
Adverse Effects
Among participants who received antibiotics, the most common adverse effects were abdominal pain or diarrhea (2.1%) and dyspepsia or poor appetite (0.8%).
