Meta-analysis of different test indicators: Helicobacter pylori infection and the risk of colorectal cancer

Impact of Helicobacter pylori Infection and Treatment on Colorectal Cancer in a Large, Nationwide Cohort

PURPOSE

Helicobacter pylori is the most common cause of infection-associated cancer worldwide. We aimed to evaluate the impact of H. pylori infection and treatment on colorectal cancer (CRC) incidence and mortality.

PATIENTS

US Veterans who completed H. pylori testing between 1999 and 2018.

METHODS

We conducted a retrospective cohort analysis among adults within the Veterans Health Administration who completed testing for H. pylori. The primary exposures were (1) H. pylori test result (positive/negative) and (2) H. pylori treatment (untreated/treated) among H. pylori-positive individuals. The primary outcomes were CRC incidence and mortality. Follow-up started at the first H. pylori testing and continued until the earliest of incident or fatal CRC, non-CRC death, or December 31, 2019.

RESULTS

Among 812,736 individuals tested for H. pylori, 205,178 (25.2%) tested positive. Being H. pylori-positive versus H. pylori-negative was associated with higher CRC incidence and mortality. H. pylori treatment versus no treatment was associated with lower CRC incidence and mortality (absolute risk reduction 0.23%-0.35%) through 15-year follow-up. Being H. pylori-positive versus H. pylori-negative was associated with an 18% (adjusted hazard ratio [adjusted HR], 1.18 [95% CI, 1.12 to 1.24]) and 12% (adjusted HR, 1.12 [95% CI, 1.03 to 1.21]) higher incident and fatal CRC risk, respectively. Individuals with untreated versus treated H. pylori infection had 23% (adjusted HR, 1.23 [95% CI, 1.13 to 1.34]) and 40% (adjusted HR, 1.40 [95% CI, 1.24 to 1.58]) higher incident and fatal CRC risk, respectively. The results were more pronounced in the analysis restricted to individuals with nonserologic testing.

CONCLUSION

H. pylori positivity may be associated with small but statistically significant higher CRC incidence and mortality; untreated individuals, especially those with confirmed active infection, appear to be most at risk.

Helicobacter pylori in Inflammatory Bowel Diseases: Active Protagonist or Innocent Bystander?

Helicobacter pylori (H. pylori) infection is a prominent entity within human infectious diseases which cause chronic gastritis, peptic ulcers, gastric malignancies, and extragastric disorders. Its persistent colonization can lead to a systemic inflammatory cascade, potentially instigating autoimmune responses and contributing to the pathogenesis of autoimmune diseases. While the specific etiopathogenesis of inflammatory bowel diseases (IBDs) is still unknown, it is widely recognized that immunological, genetic, and environmental factors are implicated. Various bacterial and viral pathogens have been implicated in the pathogenesis of IBDs. Numerous studies suggest a correlation between H. pylori infection and IBDs. While subject to debate, this link suggests that the bacterium's presence somehow impacts the progression of IBDs by modifying the diversity of the gut microbiota, consequently altering local chemical profiles and disrupting the pattern of gut immune response. However, epidemiological evidence indicates a protective role of H. pylori infection against the onset of autoimmune diseases. Additionally, laboratory findings demonstrate H. pylori's capacity to promote immune tolerance and restrict inflammatory reactions. The aim of this review is to elucidate the proposed mechanisms and confounding factors that underlie the potential association between H. pylori infection and IBDs.

Colorectal Cancer: Disease Process, Current Treatment Options, and Future Perspectives

Colorectal cancer (CRC) is one of the deadliest malignancies in the US, ranking fourth after lung, prostate, and breast cancers, respectively, in general populations. It continues to be a menace, and the incidence has been projected to more than double by 2035, especially in underdeveloped countries. This review seeks to provide some insights into the disease progression, currently available treatment options and their challenges, and future perspectives. Searches were conducted in the PubMed search engine in the university's online library. The keywords were "Colorectal Cancer" AND "disease process" OR "disease mechanisms" OR "Current Treatment" OR "Prospects". Selection criteria were original articles published primarily during the period of 2013 through 2023. Abstracts, books and documents, and reviews/systematic reviews were filtered out. Of over 490 thousand articles returned, only about 800 met preliminary selection criteria, 200 were reviewed in detail, but 191 met final selection criteria. Fifty-one other articles were used due to cross-referencing. Although recently considered a disease of lifestyle, CRC incidence appears to be rising in countries with low, low-medium, and medium social demographic indices. CRC can affect all parts of the colon and rectum but is more fatal with poor disease outcomes when it is right-sided. The disease progression usually takes between 7-10 years and can be asymptomatic, making early detection and diagnosis difficult. The CRC tumor microenvironment is made up of different types of cells interacting with each other to promote the growth and proliferation of the tumor cells. Significant advancement has been made in the treatment of colorectal cancer. Notable approaches include surgery, chemotherapy, radiation therapy, and cryotherapy. Chemotherapy, including 5-fluorouracil, irinotecan, oxaliplatin, and leucovorin, plays a significant role in the management of CRC that has been diagnosed at advanced stages. Two classes of monoclonal antibody therapies have been approved by the FDA for the treatment of colorectal cancer: the vascular endothelial growth factor (VEGF) inhibitor, e.g., bevacizumab (Avastin®), and the epidermal growth factor receptor (EGFR) inhibitor, e.g., cetuximab (Erbitux®) and panitumumab (Verbitix®). However, many significant problems are still being experienced with these treatments, mainly off-target effects, toxic side effects, and the associated therapeutic failures of small molecular drugs and the rapid loss of efficacy of mAb therapies. Other novel delivery strategies continue to be investigated, including ligand-based targeting of CRC cells.

Association between Helicobacter pylori infection and colorectal polyps

It was aimed to investigate whether the Helicobacter pylori infection is related to the frequency, localization, size and number of colorectal polyps. The data of 4561 patients who underwent esophagogastroduodenoscopy and colonoscopy were analyzed retrospectively. Patients with and without polyps at colonoscopy were grouped and the frequency of H pylori infection was compared in these patients. The relationship between the groups was evaluated with statistical methods. It was determined that the rate of H pylori infection was higher in patients with colorectal polyps than in patients without polyps (P < .005). Patients with multiple polyps, polyps larger than 1 cm, and tubulovillous and villous adenoma from polyp types had a higher rate of H pylori infection (P = .095; P .004; P .001). When the polyps were evaluated according to their localization, H pylori infection rates were not different between the groups (P = .341). It has been observed that the rate of H pylori infection is higher in large polyps, multiple polyps, tubulovillous and villous adenomas, which are known to have a higher risk of malignancy.

Helicobacter pylori infection with atrophic gastritis: An independent risk factor for colorectal adenomas

BACKGROUND

The significance of Helicobacter pylori (H. pylori) infection and atrophic gastritis (AG) in the prevalence of colorectal adenomas has been examined in a limited number of studies. However, these studies reported disputed conclusions.

AIM

To investigate whether H. pylori infection, AG, and H. pylori-related AG increase the risk of colorectal adenomas.

METHODS

This retrospective cross-sectional study included 6018 health-check individuals. The relevant data for physical examination, laboratory testing, ¹³C-urea breath testing, gastroscopy, colonoscopy and histopathological examination of gastric and colorectal biopsies were recorded. Univariate and multivariate logistic regression analyses were performed to determine the association between H. pylori-related AG and colorectal adenomas.

RESULTS

Overall, 1012 subjects (16.8%) were diagnosed with colorectal adenomas, of whom 143 (2.4%) had advanced adenomas. Among the enrolled patients, the prevalence of H. pylori infection and AG was observed as 49.5% (2981/6018) and 10.0% (602/6018), respectively. Subjects with H. pylori infection had an elevated risk of colorectal adenomas (adjusted odds ratio [OR] of 1.220, 95% confidence interval (CI): 1.053-1.413, P = 0.008) but no increased risk of advance adenomas (adjusted OR = 1.303, 95%CI: 0.922-1.842, P = 0.134). AG was significantly correlated to an increased risk of colorectal adenomas (unadjusted OR = 1.668, 95%CI: 1.352-2.059, P < 0.001; adjusted OR = 1.237, 95%CI: 0.988-1.549, P = 0.064). H. pylori infection accompanied by AG was significantly associated with an increased risk of adenomas (adjusted OR = 1.491, 95%CI: 1.103-2.015, P = 0.009) and advanced adenomas (adjusted OR = 1.910, 95%CI: 1.022-3.572, P = 0.043).

CONCLUSION

H. pylori-related AG was associated with a high risk of colorectal adenomas and advanced adenomas in Chinese individuals.

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.

H. pylori Infection and Colorectal Cancers by Anatomical Locations

Background:

H. pylori infection may play a role in the development of colorectal cancers (CRC). We aimed to examine the association between H. pylori infection and the risk of CRC by anatomical locations.

Methods:

We conducted a case-control study on 91 incidence cases of CRC and 224 hospital controls. CRC was determined by histopathological examinations. H. pylori IgG antibody in serum was tested. We collected data on the diet, nutrition, and lifestyle by the validated semi-quantitative food frequency and demographic lifestyle questionnaire. The odds ratio and 95% confidence interval (OR (95%CI) were estimated for CRC and its subgroups.

Results:

Overall 54.95% of CRC cases and 42.41% of the controls were H. pylori-seropositive, OR (95%CI): 1.56 (0.88, 2.74), p for trend=0.115. Positive dose-response association in quartiles, highest vs lowest, was observed for total CRC, OR (95%CI): 2.14 (1.00, 4.58), p for trend=0.049, for proximal colon, OR (95%CI): 1.52 (0.37, 6.25), p for trend=0.571), and for distal colon and rectum cancers combined, OR (95%CI): 2.38 (1.03, 5.50), p for trend=0.039.

Conclusions:

There is a positive association between H. pylori and colorectal cancers, especially distal colon and rectum cancers combined, but additional research is needed to determine the underlying mechanism of chronic H. pylori infection-induced CRC in humans.

Prevalence of Helicobacter pylori among Sudanese patients diagnosed with colon polyps and colon cancer using immunohistochemistry technique

Objectives

Infection with the bacteria Helicobacter pylori has been classified as class one carcinogen associated with increasing susceptibility of gastritis and gastric carcinoma. This study is aiming at investigating the prevalence of H. pylori among colon polyps and colon cancer patients. A descriptive cross-sectional hospital-based study was conducted between February and June 2017. Sixty-nine formalin-fixed paraffin blocks collected from colon polyps and colon cancer patients to detect H. pylori using immunohistochemistry technique.

Results

Of the 69 patients included in the study, 39 (56.5%) males and 30 (43.5%) were females, their age ranged from 21 to 80 years with a mean age of 47.1 ± 19.7. Of the 69 colon polyps and colon cancer patients, 44 (63.8%) were diagnosed as adenocarcinoma, 10 (14.5%) colitis, 15 (21.7%) juvenile polyposis syndrome. The results of immunohistochemistry technique showed the presence of 16 (23.2%) positive patients for H. pylori infection. Of these 16, 13 (81.3%) patients were diagnosed with adenocarcinoma and 3 (18.7%) patients were diagnosed with juvenile polyps. The results of H. pylori detection among the different colon polyps and colon cancer patients were showing a statistically significant association for H. pylori infection and adenocarcinoma, P value 0.028.

Helicobacter pylori infection coexisting with intestinal metaplasia is not associated with colorectal neoplasms

Introduction

Colorectal cancer is one of the most common cancers and is a major cause of morbidity and mortality in the world and our country. Studies have indicated that there might be a relationship between Helicobacter pylori (Hp) and colorectal neoplasia (CN), although others have not found any relationship.

Aim

To determine whether there is a potential relationship between Hp and CN in our patients.

Material and methods

A total of 314 patients, aged 16–86 years, who underwent gastroscopy and colonoscopy at our department between 2015 and 2017 were evaluated retrospectively. The age, gender, endoscopy results, presence of Hp, complete blood count (CBC), vitamin B₁₂, folic acid, C-reactive protein (CRP), and sedimentation levels of the patients were examined.

Results

CBC, ferritin, vitamin B₁₂, and CRP measurements did not show statistical significance in terms of the presence of Hp (p > 0.05). Folate values of Hp-positive patients were significantly lower than Hp-negative patients (p = 0.007; p < 0.01). No significant relationship was detected between Hp and colon cancer (p > 0.05). Adenomatous polyps were not related to Hp (p > 0.05). Correlation between intestinal metaplasia (IM) and adenomatous polyps was insignificant. There was no statistically significant difference between colon and gastric pathology results.

Conclusions

In our study, no significant relationship was noted between Hp and CN. A few studies have been conducted in our country, and our results are consistent with some of these studies while it is contradictory to others. Large populational multicentre studies are needed in order to identify the relationship between Hp and CN.

Clinical significance of serum markers reflecting gastric function and H. pylori infection in colorectal cancer

Purpose: The study was conducted to investigate the relationship of serum pepsinogens PGI, PGII, gastrin-17, and Hp-IgG with colorectal cancer (CRC), aiming to explore the clinical significance of serum markers reflecting gastric function and H. pylori infection in CRC. Methods: A total of 569 CRC cases and 569 age and sex-matched controls were enrolled in this study between June 2012 and April 2016 from The First Hospital of China Medical University. The serum markers reflecting gastric function and H. pylori infection were detected using ELISA, including PGI, PGII, PGI/II ratio, G-17 and Hp-IgG. Information of clinicopathological parameters and tumor biomarkers was collected from the medical records of inpatients, including CEA, CA199, CA125, CA153 and AFP. Results: Serum PGII, G-17 levels and Hp-IgG were increased in CRC, while PGI and PGI/II ratio appeared no significant difference between CRC and controls. In subgroup analysis, PGII was more significant in males (P=0.014). Hp-IgG was demonstrated higher in age<60y (P=0.001). With respect to the association with serum tumor biomarkers, G-17 level was associated with the rise of CA125 (P=0.005, OR (95%CI): 4.89 (1.90-12.57)), Hp-IgG increasing was associated with the rise of CA125 (P=0.024, OR (95%CI): 4.10 (1.54-10.93)). Conclusions: Serum PGII, G-17 and Hp-IgG were associated with CRC risk. The serum levels of G-17 and Hp-IgG were associated with the rise of CA125 in patients with CRC.

When Is Enough, Enough? When Are More Observational Epidemiologic Studies Needed to Resolve a Research Question: Illustrations Using Biomarker-Cancer Associations

BACKGROUND

Research reproducibility is vital for translation of epidemiologic findings. However, repeated studies of the same question may be undertaken without enhancing existing knowledge. To identify settings in which additional research is or is not warranted, we adapted research synthesis metrics to determine number of additional observational studies needed to change the inference from an existing meta-analysis.

METHODS

The fail-safe number (FSN) estimates number of additional studies of average weight and null effect needed to drive a statistically significant meta-analysis to null (P ≥ 0.05). We used conditional power to determine number of additional studies of average weight and equivalent heterogeneity to achieve 80% power in an updated meta-analysis to detect the observed summary estimate as statistically significant. We applied these metrics to a curated set of 98 meta-analyses on biomarkers and cancer risk.

RESULTS

Both metrics were influenced by number of studies, heterogeneity, and summary estimate size in the existing meta-analysis. For the meta-analysis on Helicobacter pylori and gastric cancer with 15 studies [OR = 2.29; 95% confidence interval (CI), 1.71-3.05], FSN was 805 studies, supporting futility of further study. For the meta-analysis on dehydroepiandrosterone sulfate and prostate cancer with 7 studies (OR = 1.29; 95% CI, 0.99-1.69), 5 more studies would be needed for 80% power, suggesting further study could change inferences.

CONCLUSIONS

Along with traditional assessments, these metrics could be used by stakeholders to decide whether additional studies addressing the same question are needed.

IMPACT

Systematic application of these metrics could lead to more judicious use of resources and acceleration from discovery to population-health impact.

Association between Helicobacter pylori infection and tumor markers: an observational retrospective study

OBJECTIVE

Helicobacter pylori infection is a major cause of several cancers such as gastric, pancreatic and lung. The relationship between H. pylori and tumour markers continues to remain unclear. The primary goal of this study is to clarify the associations between H. pylori infection and six tumour markers (ie, carcinoembryonic antigen (CEA), cancer antigen (CA) 153, CA199, CA724, CA125 and alpha-fetoprotein (AFP)). The secondary goal is to provide understanding for further research about H. pylori infection and gastrointestinal cancer.

DESIGN

Observational retrospective study.

SETTING

The study was performed in Beijing, China, where enrolled subjects had all passed health examinations during the period of 2012-2016. Subjects were categorised into H. pylori (+) and H. pylori (-) group according to their infection status and the measured six biomarkers. We used logistic regression models and generalised linear models to explore the associations between H. pylori infection and six tumour markers (ie, CEA, CA153, CA199, CA724, CA125 and AFP).

PARTICIPANTS

A total of 14 689 subjects were included and 6493 (44.2%) subjects were infected by H. pylori. The subjects had a mean age (1SD) of 45 (18) years. There were 4530 (31.0%) female subjects.

RESULTS

After adjusting for the confounding factors, infections with H. pylori were found to be significantly associated with abnormal ratios in CEA, AFP and CA724 of H. pylori (+) to H. pylori (-) groups. Significant positive correlation was found between H. pylori infection and CEA values (adjusted β=0.056; 95% CI 0.005 to 0.107; p=0.033).

CONCLUSIONS

In this observational retrospective study, we observed the H. pylori infections in a Chinese population and found higher CEA level in H. pylori-infected subjects and abnormal ratios in CEA, AFP and CA724 in infected subjects to uninfected subjects. These findings may provide a basis for future exploration with H. pylori and tumour markers.

The association between Helicobacter pylori infection and the risk of advanced colorectal neoplasia may differ according to age and cigarette smoking

BACKGROUND

The association between Helicobacter pylori infection and advanced colorectal neoplasia (ACN) remains controversial. This study aimed to clarify the association between H. pylori infection and ACN according to age groups.

METHODS

We retrospectively analyzed the association between H. pylori infection and ACN in patients aged <50 and ≥50 years receiving a health checkup that included colonoscopy. Helicobacter pylori positivity was determined by the results of serum anti-H. pylori immunoglobulin G or rapid urease test, if the anti-H. pylori immunoglobulin G was in the borderline range.

RESULTS

Among the 19 337 patients who were included, 56.2% and 3.4% were positive for H. pylori and ACN, respectively. Helicobacter pylori infection independently increased the risk of ACN in patients aged <50 years (odds ratio [OR], 1.602; 95% confidence intervals [CI], 1.194-2.150) but not in patients aged ≥50 years (OR, 1.046; 95% CI, 0.863-1.268). The positive association between H. pylori infection and ACN was affected by smoking history. When stratified by age and smoking history, H. pylori infection conferred an increased risk of ACN in patients aged <50 years with a history of smoking (OR, 1.926; 95% CI, 1.336-2.775) but not in the other 3 groups (3-way interaction test P = .023). Among patients aged <50 years with ACN, ACN in the left colon was found more frequently in patients with H. pylori infection and a history of smoking than in those without (69.3% vs 54.4%, respectively; P = .031).

CONCLUSIONS

Helicobacter pylori infection confers an increased risk of ACN, but the association may differ according to age and smoking history.

Characteristics and risk factors for sporadic non-ampullary duodenal adenocarcinoma

OBJECTIVES

Despite the gradual increase in the incidence of non-ampullary duodenal adenocarcinoma (NADAC), the associated characteristics and risk factors remain poorly understood. The aim of this study was to clarify the clinical characteristics and risk factors of sporadic NADAC.

MATERIALS AND METHODS

In this retrospective case-control study, we enrolled 156 Japanese NADAC patients with 160 lesions from our hospital's cancer registry over 13 years. The patient demographics and clinical findings were compared to 468 age- and sex-matched controls selected from our medical health checkup recipients.

RESULTS

The ratio of men to women among the NADAC patients was 2:1, the median age was 64 years (range 31 to 90 years), the majority of the lesions were located in the second portion of the duodenum, and well-differentiated adenocarcinoma was the dominant histology. A univariate analysis revealed that smoking was a common risk factor for both men and women, whereas Helicobacter pylori (HP) infection and a history of colorectal cancer (CRC) were risk factors for the men. The multivariate analysis revealed that smoking, a history of CRC, and HP positivity were also individual risk factors for NADAC.

CONCLUSIONS

Smoking, a history of CRC, and HP positivity were identified as risk factors for NADAC.

Helicobacter pylori Infection with Atrophic Gastritis Is an Independent Risk Factor for Advanced Colonic Neoplasm

Background/Aims

Helicobacter pylori is a major risk factor for atrophic gastritis (AG) and gastric cancer. The correlation between H. pylori, AG and colorectal neoplasm (CRN) has only been examined in a limited number of studies, and findings have been inconclusive. We aimed to investigate the association between H. pylori infection status, AG and advanced CRN.

Methods

This cross-sectional study investigated the relationship between the presence of serum anti-H. pylori IgG antibodies, AG, and advanced CRN in 6,351 consecutive asymptomatic subjects who underwent a screening colonoscopy.

Results

A total of 316 participants (5.0%) had advanced CRN. H. pylori seropositivity was 61.3%. In a univariate analysis, the presence of H. pylori infection was associated with advanced CRN (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.17 to 1.91; p=0.001). H. pylori infection was associated with an increased risk of advanced CRN after adjusting for clinically relevant confounders (OR, 1.34; 95% CI, 1.04 to 1.72; p=0.023). H. pylori-related AG was significantly associated with the risk of advanced CRN (OR, 1.40; 95% CI, 1.03 to 1.91; p=0.030), whereas H. pylori infection without AG was not.

Conclusions

H. pylori infection increased the risk of advanced CRN, especially when it was combined with AG. Strict colonoscopy screening and surveillance may be warranted in those with H. pylori-positive AG.

Helicobacter pylori Antibody Reactivities and Colorectal Cancer Risk in a Case-control Study in Spain

Background: Several studies have suggested that Helicobacter pylori (H. pylori) infection is a risk factor for colorectal cancer (CRC), while others have not confirmed this hypothesis. This work aimed to assess the relation of CRC with H. pylori seropositivity and with seropositivity to 16 H. pylori proteins, in the MultiCase-Control study, MCC-Spain.

Methods: MCC-Spain is a multicase-control study carried out in Spain from 2008 to 2013. In total, 2,140 histologically-confirmed incident CRC cases and 4,098 population-based controls were recruited. Controls were frequency-matched by sex, age, and province. Epidemiological data were collected through a questionnaire fulfilled by face-to-face interviews and a self-administered food-frequency questionnaire. Seroreactivities against 16 H. pylori proteins were determined in 1,488 cases and 2,495 controls using H. pylori multiplex serology. H. pylori seropositivity was defined as positivity to ≥4 proteins. Multivariable logistic regression mixed models were used to estimate odds ratios (OR) and 95% confidence intervals (CI).

Results:H. pylori seropositivity was not associated with increased CRC risk (OR = 0.91; 95% CI: 0.71–1.16). Among H. pylori seropositive subjects, seropositivity to Cagδ showed a lower CRC risk, and risk decreased with increasing number of proteins seropositive. Seropositivity to the most recognized virulence factors, CagA and VacA, was not associated with a higher CRC risk. No statistically significant heterogeneity was identified among tumor sites, although inverse relations were stronger for left colon cancer. An interaction with age and sex was found: H. pylori seropositivity was associated with a lower CRC risk in men younger than 65 and with a higher risk in older women.

Conclusions: Our results suggest that neither H. pylori seropositivity, nor seropositivity to the virulence factor CagA are associated with a higher CRC risk. A possible effect modification by age and sex was identified.

The Association Between Helicobacter pylori Infection and Nonalcoholic Fatty Liver Disease

PURPOSE OF REVIEW

Helicobacter pylori (HP) infection is known to be a significant risk factor in the development of certain gastric conditions, such as ulcers, gastritis, and malignancy. Recently, however, the systemic effect of HP infection on other organ systems has come to be appreciated. In this review, we will explore the association between HP infection and nonalcoholic fatty liver disease (NAFLD), the hepatic component of metabolic syndrome.

RECENT FINDINGS

The possible association between HP infection and NAFLD initially stemmed from the isolation of HP bacteria in the livers of patients with NAFLD. Although there have been conflicting results, several subsequent clinical trials have demonstrated a higher rate of fatty liver and NASH in HP-positive patients compared to HP-negative patients; in addition, small trials examining the effect of HP eradication have shown improvement in markers of NAFLD activity, further supporting a link between these two conditions. The pathophysiology behind the possible association between HP infection and NAFLD has yet to be fully elucidated; several possible mechanisms include induction of a pro-inflammatory state that shifts the body toward a more lipogenic profile, and a hormonal shift that favors progression toward insulin resistance and fibrosis. The association between HP infection and NAFLD has been demonstrated in several clinical trials, including small trials evaluating the effect of HP eradication on NAFLD. Future studies examining the pathophysiology behind this association are the next step in characterizing the relationship between these two conditions.

A simple scoring model for advanced colorectal neoplasm in asymptomatic subjects aged 40-49 years

Background

Limited data are available for advanced colorectal neoplasm in asymptomatic individuals aged 40–49 years. We aimed to identify risk factors and develop a simple prediction model for advanced colorectal neoplasm in these persons.

Methods

Clinical data were collected on 2781 asymptomatic subjects aged 40–49 years who underwent colonoscopy for routine health examination. Subjects were randomly allocated to a development or validation set. Logistic regression analysis was used to determine predictors of advanced colorectal neoplasm.

Results

The prevalence of overall and advanced colorectal neoplasm was 20.2 and 2.5% respectively. Older age (45–49 years), male sex, positive serology of Helicobacter pylori, and high triglyceride and low high-density lipoprotein (HDL) levels were independently associated with an increased risk of advanced colorectal neoplasm. BMI (body mass index) was not significant in multivariable analysis. We developed a simple scoring model for advanced colorectal neoplasm (range 0–9). A cutoff of ≥4 defined 43% of subjects as high risk for advanced colorectal neoplasm (sensitivity, 79%; specificity, 58%; area under the receiver operating curve = 0.72) in the validation datasets.

Conclusion

Older age (45–49 years), male sex, positive serology of H. pylori, high triglyceride level, and low HDL level were identified as independent risk factors for advanced colorectal neoplasm.

Helicobacter pylori infection is an independent risk factor for colonic adenomatous neoplasms

PURPOSE

Helicobacter pylori infection is considered to have a positive association with colorectal neoplasms. In this study, we evaluated the association between H. pylori infection and colorectal adenomas, based on the characteristics of these adenomas in Korea, where the prevalence of H. pylori infection is high and the incidence of colorectal cancer continues to increase.

METHODS

The study cohort consisted of 4,466 subjects who underwent colonoscopy and esophagogastroduodenoscopy during screening (1,245 colorectal adenomas vs. 3,221 polyp-free controls). We compared the rate of H. pylori infection between patients with adenoma and polyp-free control cases, using multivariable logistic regression analysis.

RESULTS

The overall rate of positive H. pylori infection was higher in adenoma cases than in polyp-free control cases (55.0 vs. 48.5%, p < 0.001). The odds ratio (OR) of positive H. pylori infection in patients with adenoma compared to polyp-free controls was 1.28 (95% CI 1.11-1.47). The positive association of H. pylori infection with colorectal adenomas was more prominent in advanced adenomas (OR 1.84, 95% CI 1.25-2.70) and multiple adenomas (OR 1.72, 95% CI 1.26-2.35). Based on the location of these adenomas, the OR was significant only in patients with colonic adenomas (OR 1.31, 95% CI 1.13-1.52) and not in those with rectal adenoma (OR 0.85, 95% CI 0.58-1.24).

CONCLUSION

Helicobacter pylori infection is an independent risk factor for colonic adenomas, especially in cases of advanced or multiple adenomas, but not for rectal adenomas.

Helicobacter Pylori Associated Gastritis Increases Risk of Colorectal Polyps: a Hospital Based-Cross-Sectional Study in Nakhon Ratchasima Province, Northeastern Thailand

BACKGROUND

Colorectal polyps are common in Thailand, particularly in the northeastern region. The present study aimed to determine any correlation between Helicobacter pylori-associated gastritis and colorectal polyps in the Thai population.

MATERIALS AND METHODS

A total of 303 patients undergoing esophagogastroduodenoscopy with colonoscopy for investigation of chronic abdominal pain participated in this study from November 2014 to October 2015. A diagnosis of Helicobacter pylori associated gastritis was made if the bacteria were seen on histopathological examination and a rapid urease test was positive. Colorectal polyps were confirmed by histological examination of colorectal biopsies. Patient demographic data were analyzed for correlations.

RESULTS

The prevalence of colorectal polyps was 77 (25.4%), lesions being found more frequently in Helicobacter pylori infected patients than non-infected subjects [38.4% vs. 12.5%; Odds Ratio (OR) (95% CI): 2.26 (1.32 - 3.86), p < 0.01]. Patients with Helicobacter pylori - associated gastritis were at high risk of having adenomas featuring dysplasia [OR (95% CI): 1.15 (1.16 - 7.99); P = 0.02]. There was no varaition in location of polyps, age group, sex and gastric lesions with respect to Helicobacter pylori status.

CONCLUSIONS

This study showed that Helicobacter pylori associated gastritis is associated with an increased risk of colorectal polyps, especially adenomas with dysplasia in the Thai population. Patients with Helicobacter pylori-associated gastritis may benefit from concurrent colonoscopy for diagnosis of colorectal polyps as a preventive and early treatment for colorectal cancer.

Long-term risk of gastrointestinal cancers in persons with gastric or duodenal ulcers

Peptic ulcer predicts gastric cancer. It is controversial if peptic ulcers predict other gastrointestinal cancers, potentially related to Helicobacter pylori or shared lifestyle factors. We hypothesized that gastric and duodenal ulcers may have different impact on the risk of gastrointestinal cancers. In a nationwide cohort study using Danish medical databases 1994-2013, we quantified the risk of gastric and other gastrointestinal cancers among patients with duodenal ulcers (dominantly H. pylori-related) and gastric ulcers (dominantly lifestyle-related) compared with the general population. We started follow-up 1-year after ulcer diagnosis to avoid detection bias and calculated absolute risks of cancer and standardized incidence ratios (SIRs). We identified 54,565 patients with gastric ulcers and 38,576 patients with duodenal ulcers. Patient characteristics were similar in the two cohorts. The 1-5-year risk of any gastrointestinal cancer was slightly higher for gastric ulcers patients (2.1%) than for duodenal ulcers patients (2.0%), and SIRs were 1.38 (95% CI: 1.31-1.44) and 1.30 (95% CI: 1.23-1.37), respectively. The SIR of gastric cancer was higher among patients with gastric ulcer than duodenal ulcer (1.92 vs. 1.38), while the SIRs for other gastrointestinal cancers were similar (1.33 vs. 1.29). Compared with gastric ulcer patients, duodenal ulcer patients were at lower risk of smoking- and alcohol-related gastrointestinal cancers. The risk of nongastric gastrointestinal cancers is increased both for patients with gastric ulcers and with duodenal ulcers, but absolute risks are low. H. pylori may be less important for the development of nongastric gastrointestinal cancer than hypothesized.

Helicobacter pylori and colorectal neoplasia: Is there a causal link?

Ever since Helicobacter pylori (H. pylori) was recognized as an infectious cause of gastric cancer, there has been increasing interest in examining its potential role in colorectal carcinogenesis. Data from case-control and cross-sectional studies, mostly relying on hospital-based samples, and several meta-analyses have shown a positive statistical relationship between H. pylori infection and colorectal neoplasia. However, the possibility exists that the results have been influenced by bias, including the improper selection of patients and disparities with respect to potential confounders. While the evidence falls short of a definitive causal link, it appears that infection with H. pylori/H. pylori-related gastritis is associated with an increased, although modest, risk of colorectal adenoma and cancer. The pathogenic mechanisms responsible for this association remain uncertain. H. pylori has been detected in colorectal malignant tissues; however, the possibility that H. pylori is a direct activator of colonic carcinogenesis remains purely hypothetical. On the other hand, experimental data have indicated a series of potential oncogenic interactions between these bacteria and colorectal mucosa, including induction and perpetuation of inflammatory responses, alteration of gut microflora and release of toxins and/or hormonal mediators, such as gastrin, which may contribute to tumor formation.

Helicobacter pylori and serum kynurenine-tryptophan ratio in patients with colorectal cancer

AIM: To evaluate how Helicobacter pylori (H. pylori) is able to evade the immune response and whether it enhances systemic immune tolerance against colorectal cancer.

METHODS: This prospective randomized study involved 97 consecutive colorectal cancer patients and 108 cancer-free patients with extra-digestive diseases. Colorectal cancer and cancer-free patients were assigned into subgroups according to H. pylori IgG seropositivity. Exposure to H. pylori was determined by IgG seropositivity which was detected by enzyme linked immunoassay (ELISA). Serum neopterin levels were measured by ELISA. Serum tryptophan, kynurenine, and urinary biopterin concentrations were measured by high performance liquid chromatography. Serum nitrite levels were detected spectrophotometrically. Serum indoleamine 2,3-dioxygenase activity was estimated by the kynurenine to tryptophan ratio and by assessing the correlation between serum neopterin concentrations and the kynurenine to tryptophan ratio. The frequencies of increased serum kynurenine to tryptophan ratio of H. pylori seronegative and seropositive colorectal cancer subgroups were estimated by comparing them with the average kynurenine to tryptophan ratio of H. pylori seronegative tumor-free patients.

RESULTS: Compared with respective controls, in both H. pylori seronegative and seropositive colorectal cancer patients, while serum tryptophan levels were decreased (controls vs patients; seronegative: 20.37 ± 0.89 μmol/L vs 15.71 ± 1.16 μmol/L, P < 0.05; seropositive: 20.71 ± 0.81 μmol/L vs 14.97 ± 0.79 μmol/L, P < 0.01) the kynurenine to tryptophan ratio was significantly increased (controls vs patients; seronegative: 52.85 ± 11.85 μmol/mmol vs 78.91 ± 8.68 μmol/mmol, P < 0.01, seropositive: 47.31 ± 5.93 μmol/mmol vs 109.65 ± 11.50 μmol/mmol, P < 0.01). Neopterin concentrations in cancer patients were significantly elevated compared with controls (P < 0.05). There was a significant correlation between serum neopterin levels and kynurenine/tryptophan in control and colorectal cancer patients groups (r_s = 0.494, P = 0.0001 and r_s = 0.293, P = 0.004, respectively). Serum nitrite levels of H. pylori seropositive cancer cases were significantly decreased compared with seropositive controls (controls vs patients; 26.04 ± 2.39 μmol/L vs 20.41 ± 1.48 μmol/L, P < 0.05) The decrease in the nitrite levels of H. pylori seropositive cancer patients may be attributed to excessive formation of peroxynitrite and other reactive nitrogen species.

CONCLUSION: A significantly high kynurenine/tryptophan suggested that H. pylori may support the immune tolerance leading to cancer development, even without an apparent upper gastrointestinal tract disease.

Application of credibility ceilings probes the robustness of meta-analyses of biomarkers and cancer risk

OBJECTIVES

Meta-analyses of biomarkers often present spurious significant results and large effects. We applied sensitivity analyses with the use of credibility ceilings to assess whether and how the results of meta-analyses of biomarkers and cancer risk would change.

STUDY DESIGN AND SETTING

We evaluated 98 meta-analyses, 43 (44%) of which had nominally statistically significant results. We assumed that any single study cannot give more than a maximum certainty 100 - c% (c, credibility ceiling) that the effect estimate [odds ratio (OR)] exceeds 1 (null) or 1.2.

RESULTS

Nominal statistical significance was maintained for 21 (21%) meta-analyses, for c = 10% and OR >1, and these proportions changed to 7%, 3%, and 6% with ceilings of 20%, 30%, and 40%, respectively. For ceilings for OR >1.2, the respective proportions were 37%, 21%, 7%, and 3%. Seven meta-analyses on infectious agents retained statistical significance even with a high ceiling of c = 20% for OR >1.00. Meta-analyses without other hints of bias (large between-study heterogeneity, small-study effects, excess significance) were more likely to retain statistical significance than those that had such hints of bias.

CONCLUSION

Credibility ceilings may be helpful in meta-analyses of biomarkers to understand the robustness of the results to different levels of uncertainty.

Duodenal adenomas coincide with colorectal neoplasia

BACKGROUND AND AIM

Small case series have alluded to an association between sporadic duodenal adenomas and colorectal neoplasia. The strength of the association remains uncertain. This case-control study was designed to test this association in a large national pathology database.

METHODS

This study, performed at Miraca Life Sciences, a specialized pathology laboratory that receives gastrointestinal biopsy specimens from outpatient centers throughout the US, included all subjects who underwent a bidirectional endoscopy with biopsy results from both procedures between January 2008 and December 2011. The association between duodenal and colonic neoplasms was investigated using odds ratios (OR) and their 95 % confidence intervals (CIs) derived from univariate and multivariate analyses.

RESULTS

There were 203,277 patients who underwent bidirectional procedures within the study period (mean age 58 years, 58 % females). Duodenal adenomas were present in 537 patients (median age 65 years, 51 % females; OR for male sex 1.34, 95 % CI 1.13-1.59). Hyperplastic colon polyps were present in 30,205 and colon adenomas in 85,801 patients. Hyperplastic polyps were more common in patients with duodenal adenomas (1.45, 1.07-1.95). Patients with duodenal adenomas also had a significantly greater prevalence of all types of colonic adenomas (2.65, 2.16-3.25), particularly of advanced adenomas (4.30, 3.24-5.70) and colorectal cancer (3.13, 1.38-7.12). Duodenal adenomas were associated with an equally increased risk for left and right colon adenomas.

CONCLUSIONS

Patients with duodenal adenomas harbor an increased risk for any type of colonic neoplasm. This association may provide new insights into the general mechanisms underlying mucosal proliferation in the gastrointestinal tract.

[Prevalence and risk factors of colorectal adenoma in 14,932 koreans undergoing screening colonoscopy]

BACKGROUND/AIMS

Current international guidelines recommend colorectal cancer screening for average-risk people over 50 years of age. Accordingly, we aimed to estimate the prevalence of colorectal neoplasms in all age groups and evaluate associated risk factors.

METHODS

Data of 14,932 subjects who underwent colonoscopy from July 2006 to January 2012 at Health Promotion Center, Gangnam Severance Hospital (Seoul, Korea) as part of a health check-up were reviewed retrospectively.

RESULTS

The overall prevalence of colorectal neoplasms and adenoma were 34.6% and 25.3%, respectively. Colorectal adenoma was found in 3.2%, 13.0%, 21.7%, 33.8%, 44.0%, 50.5%, and 54.2% of subjects under 30 years, 30-39 years, 40-49 years, 50-59 years, 60-69 years, 70-79 years, and over 80 years of age (trend p<0.0001). Independent predictors of colorectal adenoma included male gender (OR 2.38, 95% CI 2.084-2.718), positive occult blood (2.266, 1.761-2.917), positive serology of Helicobacter pylori (1.253, 1.114-1.409) and hypertriglyceremia (1.267, 1.065-1.508). Compared to the 30-39 years of age reference group, the ORs for each age group were 0.195 (under 30 years), 1.634 (40-49 years), 2.954 (50-59 years), 5.159 (60-69 years), 5.640 (70-79 years), 11.020 (over 80 years), while the 95% CIs were 0.071-0.536 (under 30 years), 1.340-1.992 (40-49 years), 2.421-3.604 (50-59 years), 4.109-6.476 (60-69 years), 3.822-8.322 (70-79 years), and 2.809-42.234 (over 80 years).

CONCLUSIONS

Colorectal adenoma prevalence increased proportionally with age. Only subjects under the age of 30 years had a definitely lower prevalence of colorectal adenoma. Male gender, positive occult blood, positive serology of H. pylori, and hypertriglyceremia were associated risk factors of colorectal adenoma.

Helicobacter pylori infection and inflammatory bowel disease: Is there a link?

Helicobacter pylori (H. pylori) infection is one of the most widely spread infectious diseases in humans. It can cause chronic gastritis, peptic ulcer disease and gastric malignancies and has been associated with extra-gastric disorders. H. pylori elicit a chronic systemic inflammatory response which, under certain conditions, may trigger autoimmune reactions and may be implicated in the pathogenesis of autoimmune diseases. Although the pathogenesis of inflammatory bowel disease (IBD) is unknown, it is thought to result from complex interactions between environmental factors and microbiota in the gut of individuals who are genetically susceptible. Several bacterial and viral agents have been implicated in the aetiology of IBD. In theory, H. pylori infection could be involved in the pathogenesis of IBD by inducing alterations in gastric and/or intestinal permeability or by causing immunological derangements resulting in absorption of antigenic material and autoimmunity via various immunological pathways. Similar mechanisms may also be responsible for the co-existence of IBD with other autoimmune diseases and/or extra-intestinal manifestations. However, the epidemiological data fail to support this association. In fact, various studies indicate that the prevalence of H. pylori infection is low in patients with IBD, suggesting a protective role for this infection in the development of IBD. In this report, we aim to shed light on proposed mechanisms and confounding factors underlying the potential link between H. pylori infection and IBD.

Prevalence of synchronous colorectal neoplasms in surgically treated gastric cancer patients and significance of screening colonoscopy

BACKGROUND AND AIM

The existence of other primary tumors during the treatment and management of gastric cancer (GC) is an important issue. The present study investigated the prevalence and management of synchronous colorectal neoplasms (CRN) in surgically treated GC patients.

METHODS

Of 381 surgically treated GC patients, 332 (87.1%) underwent colonoscopy to detect CRN before surgery or within a year after surgery.

RESULTS

CRN were synchronously observed in 140 patients (42.2%). Adenoma was observed in 131 patients (39.4%). Endoscopic resection was done in 18 patients with adenoma. Colorectal cancer (CRC) was observed in 16 patients (4.8%), superficial CRC in 13 and advanced CRC in three patients. Endoscopic resection of superficial CRC was carried out in seven patients, whereas simultaneous surgical resection of CRC was done in nine patients. CRN were more frequently observed in men. CRC was more frequently observed in GC patients with distant metastasis, albeit without significance. The overall survival of GC patients with CRN or CRC was poorer than that of patients without CRN or CRC.

CONCLUSION

Synchronous CRN were commonly associated with GC and screening colonoscopy should be offered to patients with GC.

Gastric Helicobacter pylori infection associates with an increased risk of colorectal polyps in African Americans

Background

Gastric Helicobacter pylori (H. pylori) infection and colorectal polyps are more prevalent in African Americans than in the general population. We aimed to investigate whether gastric H. pylori infection is associated with colorectal polyps in African Americans.

Methods

Medical records of African Americans, 40 years and older (n = 1256) who underwent bidirectional gastrointestinal endoscopy on the same day were reviewed. H. pylori status was assessed by immunohistochemistry on gastric specimens. Colorectal polyps were confirmed by histological examination of colorectal biopsies. A subset of serum samples from healthy and polyp-bearing patients (n = 163) were analyzed by ELISA for anti-H. pylori and anti-CagA antibodies. The crude and adjusted effect of H. pylori on the risk of colorectal adenoma and polyp were computed by logistic regression models.

Results

The prevalence of colorectal polyps and adenomas were 456 (36%) and 300 (24%) respectively. Colorectal polyps were more prevalent in gastric H. pylori infected than non-infected subjects [43% vs. 34%; Odds Ratio (OR) (95% CI): 1.5 (1.2-1.9), P = 0.001]. Patients with H. pylori-associated chronic active gastritis were at high risk to have adenomas [Unadjusted OR (95% CI): 1.3 (1.0-1.8); P = 0.04]. There was no difference in histopathology, size, or location of polyps with respect to H. pylori status. Gastric H. pylori infection, age, male gender and high risk clinical presentations were independent risk factors for colorectal polyps. Serological testing also revealed a higher prevalence of H. pylori and its toxin Cag-A in polyp patients vs. non polyp patients’ sera, although in a non-statistically significant manner.

Conclusions

This study showed that current gastric H. pylori infection is associated with an increased risk of colorectal polyps in African Americans. Patients with H. pylori induced gastritis may benefit from early screening colonoscopy as a preventative measure for 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.

Is preoperative colonoscopy necessary for patients undergoing gastric cancer surgery?

PURPOSE

The aim of this study was to evaluate the necessity of preoperative colonoscopy (CS) in gastric cancer (GC) patients and to assess the outcomes of different treatments in patients with synchronous GC and colorectal neoplasms (CRN). We also determined the risk factors influencing the comorbidity of colorectal cancer (CRC) in patients with GC.

METHODS

This retrospective study included 1891 consecutive GC patients who underwent CS before surgery from January 1, 1999, through June 30, 2012.

RESULTS

There was a high prevalence of concurrent CRN (28.4 %) and CRC (3.2 %) in our patients with GC. Sixty-one patients with GC had synchronous CRC. Twenty-three of the 61 tumors were perioperatively treated by endoscopic resection. The other 38 tumors were treated by simultaneous surgery for the GC and CRC. Surgical complications were not found in either the endoscopic or surgical resection group. The multivariate logistic regression analysis indicated that the prevalence of synchronous CRC in patients with GC was significantly associated with the incidence of multiple GCs [P < 0.0001; odds ratio (OR) 15.3], having anemia (P = 0.002; OR 3.0), and having a smoking history (P = 0.021; OR 1.9).

CONCLUSIONS

We recommend preoperative CS screening for GC patients. In particular, preoperative CS screening is indispensable for patients with multiple GCs. In addition, simultaneous treatments for patients with synchronous GC and CRN are safe and feasible procedures.

Helicobacter pylori-related chronic gastritis as a risk factor for colonic neoplasms

To summarize the current views and insights on associations between Helicobacter pylori (H. pylori)-related chronic gastritis and colorectal neoplasm, we reviewed recent studies to clarify whether H. pylori infection/H. pylori-related chronic gastritis is associated with an elevated risk of colorectal neoplasm. Recent studies based on large databases with careful control for confounding variables have clearly demonstrated an increased risk of colorectal neoplasm associated with H. pylori infection. The correlation between H. pylori-related chronic atrophic gastritis (CAG) and colorectal neoplasm has only been examined in a limited number of studies. A recent large study using a national histopathological database, and our study based on the stage of H. pylori-related chronic gastritis as determined by serum levels of H. pylori antibody titer and pepsinogen, indicated that H. pylori-related CAG confers an increased risk of colorectal neoplasm, and more extensive atrophic gastritis will probably be associated with even higher risk of neoplasm. In addition, our study suggested that the activity of H. pylori-related chronic gastritis is correlated with colorectal neoplasm risk. H. pylori-related chronic gastritis could be involved in an increased risk of colorectal neoplasm that appears to be enhanced by the progression of gastric atrophy and the presence of active inflammation.

Helicobacter pylori but not gastrin is associated with the development of colonic neoplasms

Recent studies have suggested that Helicobacter pylori (H. pylori) constitutes a risk for the development of colonic neoplasia. Hypergastrinemia can be induced by H. pylori infection, and gastrin can act as putative promoter of colorectal carcinogenesis. Aim of our study was to assess whether H. pylori infection and/or increased serum gastrin levels are associated with the occurrence of colonic neoplasms. For this, we reviewed prospectively collected data of 377 patients with a minimum age of 50 years who underwent colonoscopy. H. pylori and CagA status were determined by serology. Serum gastrin levels were measured in fasting state by commercially available assay. In H. pylori infected patients (n = 138; 36.6%), the overall prevalence of colonic neoplasms was more frequent compared to H. pylori negative patients (n = 239; 63.4%) (OR = 2.73, 95% CI: 1.76-4.24). H. pylori infection occurred more frequently in patients with hyperplastic polyps (OR = 2.66, 95% CI: 1.23-5.74) and adenomas presenting with low grade intraepithelial neoplasia (IEN) (OR = 1.85, 95% CI: 1.14-2.99). Attributable risk for adenomas with high grade IEN and colorectal adenocarcinoma (n = 14) was not assessed due to the low number of cases. The expression of CagA was also associated with an increased risk for colonic neoplasms (OR = 2.25, 95% CI: 1.29-3.94). Hypergastrinemia did not increase the risk for any colonic neoplasms and there was no difference in basal serum gastrin levels between H. pylori positive and negative patients. In conclusion, H. pylori infection, including CagA expression is associated with an increased risk for the development of colonic neoplasm.

U.S. hospitalizations for colorectal cancer 1970-2010

BACKGROUND AND AIMS

The occurrence of colorectal cancer has been declining in the United States. The aim of the present study was to confirm such time trends using hospitalization data for colorectal cancer from the past four decades.

METHODS

U.S. hospital utilization data were available for individual years from 1970 to 2010 through the National Hospital Discharge Survey. Colon and rectum cancer were analyzed separately stratified by their ICD-9CM codes. Hospitalizations during consecutive 5-year periods were expressed as annual rates per 100,000 living U.S. population.

RESULTS

After an initial rise between 1970 and 1985, U.S. hospitalizations for colorectal cancer have declined ever since. Similar trends were found in men and women, and for colon and rectum cancer analyzed separately. The rise and fall of both cancer types were statistically significant (p < 0.001). The decline was most pronounced in the 65 years and older age group.

CONCLUSIONS

Hospitalizations for colorectal cancer have declined in the United States since the mid-1980s. The onset of this decline preceded the widespread use of screening for colorectal cancer. Other mechanisms besides screening may have contributed to this observed decline.

Helicobacter pylori seropositivity is positively associated with colorectal neoplasms

BACKGROUND/AIMS

Helicobacter pylori is a well known precursor to gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. This study was to determine whether H. pylori was associated with colorectal neoplasms in Korean subjects undergoing routine checkup.

METHODS

A total of 10,082 subjects underwent routine checkups from January 2004 to April 2005. A H. pylori IgG test and stool occult blood test were included in the routine checkup program. Colonoscopy was performed if the stool occult blood test was positive or under subject request. Patients who underwent colonoscopy and had histologically confirmed cases of colorectal neoplasms were designanted as the subject group and those without as the control group.

RESULTS

Of the 10,082 subjects, 597 had full colonoscopy. The results identified 9 colorectal carcinomas and 118 adenomas. H. pylori seropositivity was identified in 6 (66%) subjects with colorectal carcinoma, 81 (68.6%) with colorectal adenoma and 248 (52.8%) controls. Subjects having colorectal neoplasms had a significantly higher H. pylori seropositivity rate compared with the controls (OR 1.94, 95% CI 1.28-2.95). This remained significant after adjusting for age, sex, body mass index, HbA1c and total cholesterol (OR 1.90, 95% CI 1.23-2.93). Patients with distal neoplasms also had a significantly higher H. pylori seroposivity rate (OR 1.88, 95% CI 1.17-3.01) which persisted after multivariate adjustment (OR 1.79, 95% CI 1.10-2.94).

CONCLUSIONS

Subjects with colorectal neoplasms present an increased H. pylori seroprevalence compared with controls.

The relationship of Helicobacter pylori infection and colon neoplasia, on the basis of meta-analysis

BACKGROUND

Helicobacter pylori is an important causative factor in gastric carcinogenesis. However, its role in extragastric gastrointestinal malignancies, such as colon neoplasia, is controversial.

AIM

The aim of this study was to explore the relationship of H. pylori infection with colon neoplasia by meta-analysis of all relevant studies.

MATERIALS AND METHODS

Pooled estimates were obtained using fixed or random-effects models as appropriate. Heterogeneity between studies was evaluated using the Cochran Q-test, whereas the likelihood of publication bias was assessed by constructing funnel plots.

RESULTS

Among 238 potentially relevant studies, 210 were rejected as unsuitable and 28 studies were finally eligible for meta-analysis, including a total of 33 sets of data (17 on colon cancer and 16 on colon polyps). There was evidence of heterogeneity (I=57.37%); thus, the random-effects model of meta-analysis was chosen, showing pooled odds ratio (OR) equal to 1.41 [95% confidence interval 1.24-1.60, P=0.000]. The subgroup meta-analyses showed a significant relationship between H. pylori and colon cancer as well as colon polyps [OR 1.3 (1.07-1.59), P=0.01 and OR 1.5 (1.26-1.79), P=0.000, respectively].

CONCLUSION

The results of this meta-analysis showed a modest statistically significant relationship of H. pylori infection with both colon cancer and polyps.

Helicobacter pylori protein-specific antibodies and risk of colorectal cancer

BACKGROUND

There is biologic plausibility as to why infection with Helicobacter pylori, the leading cause of gastric cancer, may also increase the risk of colorectal cancer, but the epidemiologic findings have been inconsistent. We assessed the association of H. pylori protein-specific infection and colorectal cancer risk in the prospective cohort, the Southern Community Cohort Study.

METHODS

Multiplex serology was used to measure antibodies to 15 H. pylori proteins in prediagnostic blood among 188 incident colorectal cancer cases and 370 controls matched by age, race, sex, and blood collection timing. Conditional logistic regression was used to calculate ORs and 95% confidence intervals (CI).

RESULTS

Overall H. pylori prevalence was not associated with colorectal cancer risk (OR, 1.03; 95% CI, 0.59-1.77). However, seropositivity to any of five specific H. pylori proteins (VacA, HP231, HP305, NapA, and HcpC) was associated with a significant 60% to 80% increase in odds of risk. These associations became even stronger when limited to colon cancer risk, particularly for the known H. pylori toxin VacA (OR, 2.24; 95% CI, 1.22-4.11), including a significant, positive dose-response association by VacA antibody levels in quartiles (P < 0.05). Associations with VacA seropositivity were especially strong for early-onset and late-stage cancers.

CONCLUSIONS

The findings raise the hypothesis that individuals with high levels of antibodies to specific H. pylori proteins may be at higher risk of colon cancer.

IMPACT

Further investigation of the H. pylori-colorectal cancer association is warranted to determine the possibility of protein-specific antibody levels as a risk biomarker.

Review article: historic changes of Helicobacter pylori-associated diseases

BACKGROUND

The long-term time trends of multiple gastrointestinal diseases are characterised by a striking rise and fall. These temporal changes provide important clues about disease aetiology.

AIM

To highlight the importance of Helicobacter pylori infection in shaping the temporal trends of many common gastrointestinal diseases.

METHODS

Literature review of the time trends associated with common digestive diseases.

RESULTS

The general trends of gastric ulcer, duodenal ulcer, gastric cancer, colon cancer, rectum cancer have all been shaped by a similar underlying birth-cohort phenomenon. Mortality associated with these diagnoses increased in all generations born during the nineteenth century. It peaked among generations born shortly before the turn of the century and then decreased in all subsequent generations born throughout the twentieth century. These patterns can be observed in the incidence, hospitalisation and mortality data from many different countries. They reflect similar rising and falling trends of H. pylori infection in the general population. Diseases that are inversely associated with H. pylori, such as reflux disease, erosive oesophagitis, Barrett's oesophagus, and oesophageal adenocarcinoma, have seen a striking rise during the recent decline of H. pylori infection.

CONCLUSION

The temporal variations of H. pylori infection have affected the occurrence of gastroenterology's most common disorders.

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

AIM

The existing evidence on the relationship between Helicobacter pylori infection and the risk of colorectal neoplasia 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.

METHOD

We searched the PubMed database and the reference lists of pertinent articles published up to July 2012. Summary odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated using a random-effects model.

RESULTS

Twenty-seven studies including 3792 cases of colorectal adenoma (CRA) and 3488 cases of colorectal cancer (CRC) were identified. Overall, H. pylori infection was associated with an increased risk of CRA (OR = 1.66, 95% CI 1.39-1.97, I(2)  = 54.3%) and CRC (OR = 1.39, 95% CI 1.18-1.64, I(2)  = 35.8%), although there was significant heterogeneity among the studies. Subgroup analysis revealed that the positive correlation did not differ by sex, geographic variation or subsite of neoplasia, but might vary by the method of detection of H. pylori. The study was underpowered to determine the risk of colorectal neoplasia associated with cytotoxin-associated gene A-positive H. pylori.

CONCLUSION

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

Significance of infectious agents in colorectal cancer development

Colorectal cancer (CRC) is a major burden to healthcare systems worldwide accounting for approximately one million of new cancer cases worldwide. Even though, CRC mortality has decreased over the last 20 years, it remains the third most common cause of cancer-related mortality, accounting for approximately 600,000 deaths in 2008 worldwide. A multitude of risk factors have been linked to CRC, including hereditary factors, environmental factors and inflammatory syndromes affecting the gastrointestinal tract. Recently, various pathogens were added to the growing list of risk factors for a number of common epithelial cancers, but despite the multitude of correlative studies, only suggestions remain about the possible relationship between selected viruses and bacteria of interest and the CRC risk. United States military service members are exposed to various risk factors impacting the incidence of cancer development. These exposures are often different from that of many sectors of the civilian population. Thereby, cancer risk identification, screening and early detection are imperative for both the military health care beneficiaries and the population as a whole. In this review, we will focus on several pathogens and their potential roles in development of CRC, highlighting the clinical trials evaluating this correlation and provide our personal opinion about the importance of risk reduction, health promotion and disease prevention for military health care beneficiaries.

Helicobacter pylori is a risk factor for colonic neoplasms

OBJECTIVES

It has been suggested that Helicobacter pylori (H. pylori) constitutes a risk for the development of adenomatous polyps and adenocarcinoma of the colon. Our aim was to study the association between H. pylori-positive gastritis and the occurrence of any colonic neoplasm.

METHODS

From a computerized database of surgical pathology reports, we selected 156,000 subjects who underwent colonoscopy and esophago-gastro-duodenoscopy with biopsy results from both procedures.

RESULTS

Compared with normal gastric mucosa, H. pylori gastritis occurred more frequently among patients with hyperplastic polyps (OR=1.24, 95% CI: 1.18-1.30), adenomatous polyps (1.52, 1.46-1.57), advanced adenomas (1.80, 1.69-1.92), villous adenomas or adenomas with high-grade dysplasia (1.97, 1.82-2.14), and adenocarcinomas (2.35, 1.98-2.80). Similarly, the strength of the association between H. pylori-positive gastritis and colonic neoplasm increased with size and number of the adenomas. The association between H. pylori gastritis and the occurrence of colonic neoplasm was similar for different locations of the large bowel. Other gastric conditions etiologically associated with H. pylori, such as intestinal metaplasia, adenoma, lymphoma, and adenocarcinoma, were also significantly associated with an increased risk of colonic neoplasm.

CONCLUSIONS

Various forms of gastritis related to H. pylori infection confer an increased risk for colonic neoplasm. In the past, when H. pylori infection was more prevalent, its attributable risk to the occurrence of colorectal neoplasm may have been quite substantial.

Effects of birth cohort on long-term trends in mortality from colorectal cancer

BACKGROUND & AIMS

The decrease in mortality from colorectal cancer might have begun before widespread use of screening colonoscopy and sigmoidoscopy examinations. We examined long-term time trends in colorectal cancer mortality in 6 European countries to determine when the reduction began.

METHODS

We analyzed mortality data from the national statistical offices of the United Kingdom (England and Wales), France, Italy, The Netherlands, Sweden, and Switzerland during the past 66 to 107 years. The data were made available by the national statistical offices of the 6 countries. Age-specific rates of death were plotted against the period of death, as period-age contours, and against the period of birth, as cohort-age contours.

RESULTS

Long-term time trends in mortality from cancers of the rectum and colon each increased among generations born from 1800 to 1880, and then decreased among all subsequent generations, in all 6 countries analyzed. Similar temporal patterns also were observed when data from men and women were analyzed separately. The birth cohort patterns of colorectal cancer mortality resemble those of gastric cancer and peptic ulcer.

CONCLUSIONS

Time trends of mortality from colorectal cancer, in 6 European countries, are associated with birth cohort patterns: colorectal cancer mortality decreased among all generations since 1880. These patterns indicate that in addition to the use of screening colonoscopy, other factors, such as changes in Helicobacter pylori infection, may have affected mortality.

Helicobacter pylori: clinical management

PURPOSE OF REVIEW

Progress continues in our understanding of the role of Helicobacter pylori infection in gastroduodenal as well as extragastric disorders. This review gives an overview on selected areas of the H. pylori infection and their clinical implications.

RECENT FINDINGS

Indications for therapy have been extended and now include idiopathic thrombocytopenic purpura, iron deficiency anemia, and vitamin B12 deficiency. New data are presented on the role of H. pylori in neurodegenerative disorders and in the metabolic syndrome. H. pylori is associated with a (small) increase in the risk for colorectal adenoma and colon cancer. The biggest challenge is the selection of new therapies and treatment strategies because of the increasing failure of standard triple therapies. The best option in high clarithromycin resistance areas is bismuth-based quadruple therapy. Probiotic bacteria and yeasts reduce adverse effects of standard H. pylori eradication regimens. In gastric cancer prevention, screening programs based on the serological detection of preneoplastic conditions may prove useful.

SUMMARY

New algorithms for preventing H. pylori-induced disease and eradicating the organism should be individualized.

Evaluation of excess statistical significance in meta-analyses of 98 biomarker associations with cancer risk

BACKGROUND

Numerous biomarkers have been associated with cancer risk. We assessed whether there is evidence for excess statistical significance in results of cancer biomarker studies, suggesting biases.

METHODS

We systematically searched PubMed for meta-analyses of nongenetic biomarkers and cancer risk. The number of observed studies with statistically significant results was compared with the expected number, based on the statistical power of each study under different assumptions for the plausible effect size. We also evaluated small-study effects using asymmetry tests. All statistical tests were two-sided.

RESULTS

We included 98 meta-analyses with 847 studies. Forty-three meta-analyses (44%) found nominally statistically significant summary effects (random effects). The proportion of meta-analyses with statistically significant effects was highest for infectious agents (86%), inflammatory (67%), and insulin-like growth factor (IGF)/insulin system (52%) biomarkers. Overall, 269 (32%) individual studies observed nominally statistically significant results. A statistically significant excess of the observed over the expected number of studies with statistically significant results was seen in 20 meta-analyses. An excess of observed vs expected was observed in studies of IGF/insulin (P ≤ .04) and inflammation systems (P ≤ .02). Only 12 meta-analyses (12%) had a statistically significant summary effect size, more than 1000 case patients, and no hints of small-study effects or excess statistical significance; only four of them had large effect sizes, three of which pertained to infectious agents (Helicobacter pylori, hepatitis and human papilloma viruses).

CONCLUSIONS

Most well-documented biomarkers of cancer risk without evidence of bias pertain to infectious agents. Conversely, an excess of statistically significant findings was observed in studies of IGF/insulin and inflammation systems, suggesting reporting biases.

Investigation of relationship between Helicobacter pylori infection and risk of colorectal carcinoma

AIM: To investigate the relationship between Helicobacter pylori (H. pylori) infection and risk of colorectal carcinoma (CRC).

METHODS: Forty patients with CRC, 40 patients with colorectal adenomatous polyps (CAP), and 40 normal controls were included. Biopsies were taken from colorectal neoplasms in patients with CRC or CAP and from normal colorectal tissue in normal controls. Pathologic diagnosis was made by hematoxylin and eosin (HE) staining. H. pylori infection was detected by silver staining.

RESULTS: The detection rate of H. pylori infection was 27.5% in patients with CRC, 35.0% in patients with CAP, and 12.5% in normal controls. Although the detection rate of H. pylori infection in patients with CRC was higher than those in patients with CAP and normal controls, no statistical significance was observed between them (both P > 0.05). The detection rate of H. pylori infection in patients with CAP was significantly higher than that in normal controls (P < 0.05).

CONCLUSION: The detection rate of H. pylori infection in patients with colorectal neoplasms was higher than that in normal controls, indicating that H. pylori infection is a risk factor for colorectal neoplasms.

Helicobacter pylori: gastric cancer and extragastric intestinal malignancies

The greatest challenge in Helicobacter pylori-related diseases continues to remain prevention of gastric cancer. New evidence supports the beneficial effect of H. pylori eradication not only on prevention of gastric cancer but also on the regression of preneoplastic conditions of the gastric mucosa. Concerning early detection of gastric cancer there are still no adequate means and there is urgent need to define appropriate markers, for example, by genome-wide research approaches. Currently, the best available method is the "serologic" biopsy based on pepsinogen I and the pepsinogen I/II ratio for identification of patients with severe gastric atrophy at increased risk for gastric cancer development. The treatment of early gastric cancer by endoscopic techniques can be performed safely and efficiently, but patients need meticulous follow-up for detection of metachronous lesions. In case of advanced disease, laparoscopically assisted surgical procedures are safe and favorable compared to open surgery. Two phase III trials support the role of adjuvant systemic treatment with different regimens. Unfortunately, there is still only slow progress in the development of palliative treatment regimens or modification of the existing therapy protocols. There is accumulating evidence for a role of H. pylori infection also in colorectal carcinogenesis. Seropositive individuals are at higher risk for the development of colorectal adenomas and consequently adenocarcinomas of this anatomical region. This phenomenon can partly be attributed to the increase of serum gastrin as response to atrophic changes of the gastric mucosa.