Exposure to Helicobacter pylori, recognized for its association with gastric cancer, may also contribute to the risk of developing colorectal cancer (CRC), according to findings from a risk-attribution modeling study.
Study Findings
Based on analyses from 43 studies, exposure to H. pylori was linked to a 1.59-fold increased risk of CRC (95% CI 1.36-1.87), as reported by Dr. Shailja C. Shah and colleagues from the University of California San Diego in eGastroenterology.
When using a pooled risk-attribution model, an estimated 22% (95% uncertainty interval [UI] 14.7-29.4) of global CRC cases were potentially related to H. pylori exposure. However, this estimate decreased to 11.9% (95% UI 0.7-22.8) when risk estimates were derived from 14 population-based and cohort studies.
Eradication and Risk Reduction
In limited observational studies, the eradication of H. pylori was linked to a reduced risk of CRC, but this effect was only observable after 10 years of follow-up.
The authors emphasized that these findings should be viewed as exploratory, urging for further well-designed studies to establish a causal relationship between H. pylori and CRC.
Significance of Findings
Despite the ongoing debate over its role in CRC, the findings are significant, particularly given the success of population-level H. pylori screening and eradication programs aimed at preventing gastric cancer. These initiatives highlight the potential dual advantage of eradicating H. pylori to reduce CRC risk, especially in areas with high prevalence and limited resources.
Classifications and Associations
Due to its established link with gastric cancer, the International Agency for Research on Cancer has classified H. pylori as a group 1 human carcinogen. However, its association with colorectal cancer remains controversial, even as evidence continues to accumulate.
For example, past research indicated that H. pylori may increase the likelihood of developing CRC by 18% and the risk of dying from CRC by 12%, particularly in U.S. military veterans.
Nonetheless, the authors acknowledged that to date, evidence supporting a clear exposure-response relationship remains incomplete.
Future Research Needs
The primary aim of the study was to provide valuable evidence to inform public health initiatives and research prioritization, assisting in the development of infection-targeted cancer prevention strategies at both global and regional levels, extending beyond H. pylori eradication to prevent gastric cancer.
The research compiled data from systematic reviews and meta-analyses, categorized by region, diagnostic method, and eradication status. Estimates of CRC cases were sourced from the Global Cancer Observatory.
Proportions of CRC cases attributable to H. pylori exposure varied when stratified by sex, age, region, and country.
Notably, women demonstrated higher estimated proportions of CRC cases potentially related to H. pylori exposure compared to men (24.8% vs 19.9%).
Age and Regional Variations
The data indicated that the proportion of CRC cases linked to H. pylori exposure grew among recent birth cohorts, rising from 9.5% for those born before 1947 to 15% for those born between 1963 and 1977.
The highest age-standardized incidence rates of CRC potentially connected to H. pylori exposure were recorded in Japan (9.0 per 100,000), Portugal (8.4 per 100,000), and South Korea (7.8 per 100,000). In contrast, the age-standardized incidence rate for the U.S. stood at 2.5 per 100,000.
Regions such as the Western Pacific and Mongolia presented the highest estimated proportions of CRC cases potentially linked to H. pylori exposure (25% and 36%, respectively). Conversely, despite a similarly high prevalence of H. pylori in Africa, South-East Asia, and the Eastern Mediterranean, these areas exhibited lower estimated proportions of CRC cases.
The researchers acknowledged that direct evidence evaluating H. pylori eradication and subsequent CRC risk remains limited and predominantly observational. Most studies are constrained by short follow-up periods and potential confounding variables.
Consequently, the conclusions of this study should be interpreted as hypothesis-generating, and further prospective and interventional studies are necessary.
Disclaimer: The information provided is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
Fuente: https://www.medpagetoday.com/gastroenterology/coloncancer/122942
Join the doctors who get the most relevant medical news, curated by specialty, every week — no spam, unsubscribe anytime.
