Association of Helicobacter pylori with colorectal cancer development

Association between Helicobacter pylori infection and the risk of colorectal cancer: A systematic review and meta-analysis

BACKGROUND

The existing evidence on the relationship between Helicobacter pylori infection and the risk of colorectal cancer is inconsistent. We conducted a systematic review with a meta-analysis to explore this relationship and to determine whether the relationship varies according to the study characteristics.

METHODS

We searched the PubMed, OVID, EMBASE database, and the reference lists of pertinent articles published up to October 2019 by 2 researchers independently. Summary odds ratios (OR) with their 95% confidence intervals (CIs) were estimated using a random-effects model.

RESULTS

Forty seven studies including 17,416 cases of colorectal cancer (CRC) and 55,811 cases of control were included. Overall, H. pylori infection was associated with an increased risk of CRC (OR = 1.70 95% CI 1.64-1.76, I = 97%), although there was significant heterogeneity among the studies. Subgroup analysis revealed that the positive correlation might vary by the design of study conducted.

CONCLUSION

This meta-analysis demonstrates a positive association between H. pylori infection and the risk of colorectal cancer.

Helicobacter pylori infection and normal colorectal mucosa-adenomatous polyp-adenocarcinoma sequence: a meta-analysis of 27 case-control studies

AIM

The study aimed to determine whether Helicobacter pylori infection is associated with colorectal adenocarcinoma and to quantify the extent of the risk.

METHOD

A literature search was performed to identify studies published between 1995 and 2012 for relevant risk estimates. Fixed and random effect meta-analytical techniques were conducted for colorectal adenocarcinoma and adenomatous polyp.

RESULTS

Twenty-seven case-controlled studies involving 3450 adenocarcinoma patients, 1304 adenomatous polyp patients and more than 4000 controls were included. Helicobacter pylori was associated with an increased risk of colorectal adenocarcinoma and adenomatous polyp [odds ratio (OR) 1.24, 95% CI 1.12-1.37, P = 0.66; OR 1.87, 95% CI 1.53-2.28, P = 0.81]. There was a significant association between the CagA-positive strain and adenocarcinoma risk (OR 1.22, 95% CI 1.08-1.37, P = 0.05). In addition, there was an increased risk of tubular adenoma and villous adenoma formation (OR 3.06, 95% CI 1.98-4.73, P = 0.14; OR 2.05, 95% CI 0.84-4.97, P = 0.86).

CONCLUSION

The meta-analysis suggests a promoting effect of Helicobacter pylori on the risk of adenocarcinoma. It also suggests that Helicobacter infection might have its influence at the start of the adenomatous polyp disease sequence.

The relationship between Helicobacter pylori and cancer risk

OBJECTIVES

This study investigated the correlation between Helicobacter pylori (HP) and cancer risk. We compared the age, sex, and comorbidity of cancer patients both infected and not infected by HP.

METHODS

In this study, we compared a comparison cohort (N=24,088) and an HP cohort (N=6022), both taken from the NHI database. We performed a statistical analysis with the multivariable Cox proportional model to estimate the risk of developing cancer for a comparison and the HP cohort.

RESULTS

Our results showed that the proportion of peptic ulcers in the HP cohort was nearly 4 times higher than that in the comparison cohort. The HP cohort was significantly associated with increased colorectal (HR=1.73, 95% CI=1.08-2.77), stomach (HR=5.21, 95% CI=2.46-11.05) and pancreatic (HR=2.77, 95% CI=1.04-7.39) cancer risks compared to the comparison cohort. In addition, the cancer risk in the HP cohort was considerably higher than that in the comparison cohort when hypertension was absent in both cohorts.

CONCLUSIONS

In this study, we proposed a method to investigate the correlation between HP infection and cancer risk. We found that HP infection is associated with the development of colorectal, stomach, and pancreatic cancers, and could thus be an independent carcinogenic risk factor.