The association of Helicobacter pylori with Colorectal Carcinoma

Abstract

Background: Colorectal cancer (CRC) is the third most common cancer worldwide; and there is now a growing body of evidence to prove that pathogens play a role in its development. The association between Helicobacter pylori and CRC remains controversial, with a number of different methodologies being employed to look into said association including serological studies, urea-based studies, stool antigen studies, histological studies and molecular studies. Aims: Broadly this study aims to calculate the prevalence of H pylori in colorectal tissue of the Maltese population, and to determine whether there is a statistically significant association between H pylori presence in colorectal tissue of Maltese nationals and the risk of CRC, when correcting for confounding demographic factors. The study also aims to determine whether there is a positive association for the presence of H pylori in CRC tissue dependent on the anatomic sub-sites of CRC. Methodology: A retrospective case-control analysis was performed to compare patients with a histological confirmed diagnosis of CRC to those with patients having no abnormal histological findings. After appropriate ethical clearance, colorectal tissue from the two patient groups was retrieved from the Mater Dei Hospital archive and tested for the presence of H pylori using PCR to detect the urease gene. Participants were also asked to complete a questionnaire regarding demographic factors. Results from the questionnaire and the PCR study were then compared statistically for the two groups. Results: 53 patients were included in the CRC group, and 53 in the control group. There were no statistically significant differences between the two groups after statistical analysis using multivariate logistical regression, except for age (p = 0.00001). The prevalence of H pylori positivity was found to be 0% (n = 0) in the CRC group and 5.66% (n = 3) in the control group. Therefore, no association could be made between H pylori and CRC in the Maltese population and no difference in terms of H pylori positivity could be extrapolated for anatomical sub-site. Conclusion: Few studies have employed PCR to prove this association; the majority of which have yielded negative results, as in this Maltese cohort. Malta registers a higher rate than most other Mediterranean nations for CRC mortality. Whilst this study showed that H pylori is unlikely to contribute to CRC development in the Maltese population, further studies looking into local epidemiological factors, the microbiome and carcinogenesis should be considered.