Highlight
- Helicobacter pylori (H. pylori) infection is associated with an increased risk of colorectal cancer (CRC), especially in genetically susceptible individuals.
- The risk is further elevated in individuals seropositive for key H. pylori virulence factors: CagA, HpaA, Omp, and HP0305.
- H. pylori eradication treatment reduces CRC risk in the Shandong Intervention Trial (SIT) but shows benefit mainly among high genetic risk subgroups in the larger Mass Intervention Trial in Linqu (MITS).
- Long-term follow-up up to nearly 30 years supports a sustained protective effect of successful H. pylori eradication in select populations.
Background
Colorectal cancer (CRC) represents a substantial global health burden as one of the leading causes of cancer morbidity and mortality worldwide. Modifiable risk factors, including infectious agents, are under investigation for their contribution to CRC pathogenesis. Helicobacter pylori, a well-established gastric carcinogen implicated in gastric adenocarcinoma, has been hypothesized to influence colorectal carcinogenesis, though evidence remains mixed. Understanding the relationship between H. pylori infection and CRC risk is clinically important, particularly in regions with high H. pylori prevalence and CRC incidence. Furthermore, genetic predisposition may modulate individual susceptibility to infection-induced carcinogenesis, advocating for a personalized preventive approach. This study synthesizes evidence from two large randomized intervention trials from Shandong Province, China, providing critical insights into the interplay between H. pylori infection, treatment, genetic risk, and colorectal cancer incidence.
Study Design
This investigation is based on data from two randomized trial cohorts:
1. Shandong Intervention Trial (SIT): Enrolled 3,365 participants between 1995 and 2024, with long-term follow-up spanning a median of 29.4 years. Participants were randomized to receive H. pylori antibiotic treatment or placebo.
2. Mass Intervention Trial in Linqu, Shandong Province (MITS): A considerably larger cohort comprising 180,284 participants enrolled from 2011 to 2024. Within MITS, a case-cohort design was additionally applied to analyze colorectal cancer risk linked to specific H. pylori virulence antigen seropositivity and host genetic susceptibility.
Key aspects of the study included:
– Assessment of baseline H. pylori infection status by serology.
– Randomized administration of antibiotic eradication therapy targeting H. pylori.
– Measurement of host genetic predisposition utilizing a Polygenic Risk Score (PRS), with particular focus on individuals in the top decile.
– Evaluation of H. pylori virulence factor seropositivity, specifically targeting CagA, HpaA, Omp, and HP0305 antigens.
– Primary endpoint was incident colorectal cancer diagnosis during follow-up.
Key Findings
Risk Associated with H. pylori Infection:
Across both cohorts, H. pylori seropositivity without receiving targeted antibiotic treatment was associated with a significantly increased risk of colorectal cancer:
– In SIT, the hazard ratio (HR) was 2.96 (95% CI 1.30 to 6.71), indicating nearly a threefold increased risk.
– In MITS, a more modest yet statistically significant increased risk was observed (HR 1.27, 95% CI 1.04 to 1.55).
Subgroup analysis revealed pronounced risk elevations among participants seropositive for all four major H. pylori virulence antigens (CagA, HpaA, Omp, HP0305). This suggests that specific bacterial strains with enhanced pathogenicity may drive colorectal carcinogenesis.
Moreover, individuals with a high genetic predisposition (top decile of PRS) exhibited a stronger association between H. pylori infection and CRC risk, highlighting gene–environment interactions critical to carcinogenic processes.
Effect of H. pylori Eradication Treatment:
– SIT demonstrated a significant 53% reduction in colorectal cancer risk post-treatment over a median 29.4-year follow-up (HR=0.47, 95% CI 0.22 to 0.99).
– Participants within SIT who achieved confirmed successful eradication saw an even greater protective effect (HR=0.38, 95% CI 0.15 to 0.94).
In contrast, MITS did not show a clear overall benefit of H. pylori treatment on CRC incidence at the median 13.8 years of follow-up (HR=1.17, 95% CI 0.95 to 1.43). Nonetheless, beneficial effects were evident within subgroups:
– Individuals at high genetic risk (top PRS decile).
– Participants seropositive for the key virulence antigens.
The diverging findings between SIT and MITS may relate to differences in follow-up duration, population characteristics, or H. pylori strain distribution.
Expert Commentary
The study provides compelling, high-quality evidence linking H. pylori infection to colorectal carcinogenesis, especially in genetically predisposed individuals and in the presence of bacterial virulence factors. These findings extend the oncogenic implications of H. pylori beyond gastric pathology and suggest a broader role in gastrointestinal malignancies.
The benefit of eradication therapy demonstrated in SIT highlights the potential for targeted H. pylori treatment as a CRC preventive strategy, particularly for high-risk groups. The absence of consistent benefit in the larger MITS cohort overall, but presence in select high-risk subpopulations, underscores the need for personalized intervention approaches based on combined microbial and host genetic risk profiling.
Limitations include potential post hoc observational analyses inherent to trial follow-up data, possible differences in antibiotic regimens and eradication success, and varying follow-up durations impacting the detection of preventive effects. Generalizability to Western populations with differing H. pylori prevalence and CRC risk requires further validation.
Biologically, H. pylori’s influence on CRC may involve systemic inflammatory responses, alterations in gut microbiota, and direct mucosal damage mediated by virulence factors such as CagA—each potentially modulated by host genetic factors regulating immune and epithelial cell functions.
Conclusion
This robust analysis from two large randomized trials establishes a significant association between H. pylori infection and increased colorectal cancer risk, strengthened by genetic susceptibility and infection with virulent bacterial strains. Eradication treatment effectively reduces CRC risk in long-term follow-up, particularly in genetically high-risk individuals and those harboring virulent H. pylori strains. These findings support integrating H. pylori screening and eradication, alongside genetic risk stratification, into colorectal cancer prevention strategies, especially in high-prevalence regions. Future research should focus on elucidating precise pathogenic mechanisms, optimizing eradication protocols, and conducting randomized trials in diverse populations to confirm these findings and inform clinical guidelines.
Funding and Clinical Trials Registration
Details regarding funding sources and clinical trial registration identifiers were not provided within the manuscript abstract but are likely documented within the full publication.
References
Han X, Xu HM, Liu ZC, et al. Helicobacter pylori infection, treatment and colorectal cancer risk by genetic predisposition: evidence from two randomised trials. Gut. 2026 Jun 30; [PMID: 42379837]. Available from: https://pubmed.ncbi.nlm.nih.gov/42379837/.
Additional relevant literature supporting context and biological plausibility includes:
– Mabe K, Kartika AV, et al. Helicobacter pylori infection and extragastric cancers: a systematic review. Helicobacter. 2021;26(5):e12856.
– Doulberis M, Schizas D, et al. Helicobacter pylori infection and colorectal cancer: Is there an actual association? World J Gastroenterol. 2019;25(20):2431-2442.
– Polyak K. Colorectal cancer: molecular pathogenesis and therapeutic implications. Hematol Oncol Clin North Am. 2018;32(4):591-607.
The integration of these findings paves the way for targeted prevention in colorectal cancer by combining microbial eradication with genetic risk assessment.