Helicobacter pylori recurrence after eradication in Latin America: Implications for gastric cancer prevention

AIM

To estimate Helicobacter pylori (H. pylori) recurrence rate in Latin America, a region with a significant H. pylori prevalence and gastric cancer burden.

METHODS

PubMed, LILACS, SciELO, Cochrane databases and abstracts from relevant meetings were reviewed. Information collected included: Participants’ characteristics, recruitment strategy, diagnostic modality, treatment arms, follow-up and recurrence rates. Recurrence was calculated using 100-patients-year rates, and data were pooled using a random effects model. The I² statistic assessed between study heterogeneity. Meta-regression analyses evaluated for effect modifying variables.

RESULTS

Literature search yielded 163 articles. Twelve studies involving 4848 patients from 9 countries met inclusion criteria. Four hundred and thirty-two reinfections were recorded in 5487 person-years of follow-up. Pooled analysis showed a recurrence rate of 7.9 cases per 100 person-years (95%CI: 5.3-10.5). Meta-regression revealed that neither the antibiotic schema, a second antibiotic course, nor the diagnostic modality had an impact on the observed risk of recurrence. The recurrence rate in the first year after treatment, predominantly recrudescence, was 11.2 (6.1-16.4) per 100 patient years. Recurrence in subsequent years, was only 6.2 (3.8-8.7).

CONCLUSION

H. pylori recurrence rates in Latin America are significant, and with geographic variability, yet are acceptable based upon the current literature for consideration of large scale intervention trials. Further research in Latin America is warranted to evaluate the efficacy, cost-effectiveness, and potential adverse outcomes of proposed eradication programs.

Draft Genome Sequences of 13 Colombian Helicobacter pylori Strains Isolated from Pacific Coast and Andean Residents

We present here the draft genomes of 13 Helicobacter pylori strains isolated from Colombian residents on the Pacific coast (n = 6) and in the Andes mountains (n = 7), locations that differ in gastric cancer risk. These 13 strains were obtained from individuals with diagnosed gastric lesions.

[Survival of Gastric Cancer in Western Honduras Pilot study: 2002-2012]

BACKGROUND

Gastric cancer is the second leading cause of cancer death globally. In Honduras the incidence in the last decade was 39 and 21 per 100,000 inhabitants for men and women, respectively. In 2008 IARC (GLOBOCAN) placed Honduras as the country with the highest incidence of gastric cancer in Latin America.

METHODS

A retrospective cohort study of patients diagnosed with gastric cancer at the Hospital de Occidente between 2002-2012 was designed. A sample of 144 patients was selected from a total of 490 to obtain a confidence level of 95%. The data collection was obtained by verbal autopsy. Prognostic factors of survival were analyzed using Cox proportional hazards ratio models (CI: 95%).

OUTCOMES

The male/female ratio was 2.8:1. The mean age was 63.29 years. Overall five-year survival was 9.39%. Among patients receiving dual therapy (surgery and chemotherapy), a statistically significant increase in survival was found (10.42%, p=0.048). Between the proximal (28.95%) and distal (56.58%) locations also a statistically significant difference was observed (p=0.03). There was no statistically significant difference in the macroscopic (Borrmann) and microscopic findings (Lauren).

DISSCUSION

This study represents the first effort to estimate survival of gastric cancer in Honduras. Survival may be linked to the location of the primary lesion and the type of treatment. It is expected to develop studies with greater coverage, to answer these questions.

Hydrogen Metabolism in Helicobacter pylori Plays a Role in Gastric Carcinogenesis through Facilitating CagA Translocation

A known virulence factor of Helicobacter pylori that augments gastric cancer risk is the CagA cytotoxin. A carcinogenic derivative strain, 7.13, that has a greater ability to translocate CagA exhibits much higher hydrogenase activity than its parent noncarcinogenic strain, B128. A Δhyd mutant strain with deletion of hydrogenase genes was ineffective in CagA translocation into human gastric epithelial AGS cells, while no significant attenuation of cell adhesion was observed. The quinone reductase inhibitor 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO) was used to specifically inhibit the H2-utilizing respiratory chain of outer membrane-permeabilized bacterial cells; that level of inhibitor also greatly attenuated CagA translocation into AGS cells, indicating the H2-generated transmembrane potential is a contributor to toxin translocation. The Δhyd strain showed a decreased frequency of DNA transformation, suggesting that H. pylori hydrogenase is also involved in energizing the DNA uptake apparatus. In a gerbil model of infection, the ability of the Δhyd strain to induce inflammation was significantly attenuated (at 12 weeks postinoculation), while all of the gerbils infected with the parent strain (7.13) exhibited a high level of inflammation. Gastric cancer developed in 50% of gerbils infected with the wild-type strain 7.13 but in none of the animals infected with the Δhyd strain. By examining the hydrogenase activities from well-defined clinical H. pylori isolates, we observed that strains isolated from cancer patients (n = 6) have a significantly higher hydrogenase (H2/O2) activity than the strains isolated from gastritis patients (n = 6), further supporting an association between H. pylori hydrogenase activity and gastric carcinogenesis in humans.

IMPORTANCE

Hydrogen-utilizing hydrogenases are known to be important for some respiratory pathogens to colonize hosts. Here a gastric cancer connection is made via a pathogen's (H. pylori) use of molecular hydrogen, a host microbiome-produced gas. Delivery of the known carcinogenic factor CagA into host cells is augmented by the H2-utilizing respiratory chain of the bacterium. The role of hydrogenase in carcinogenesis is demonstrated in an animal model, whereby inflammation markers and cancer development were attenuated in the hydrogenase-null strain. Hydrogenase activity comparisons of clinical strains of the pathogen also support a connection between hydrogen metabolism and gastric cancer risk. While molecular hydrogen use is acknowledged to be an alternative high-energy substrate for some pathogens, this work extends the roles of H2 oxidation to include transport of a carcinogenic toxin. The work provides a new avenue for exploratory treatment of some cancers via microflora alterations.

Epigenetic and genetic variation in GATA5 is associated with gastric disease risk

Gastric cancer incidence varies considerably among populations, even those with comparable rates of Helicobacter pylori infection. To test the hypothesis that genetic variation plays a role in gastric disease, we assessed the relationship between genotypes and gastric histopathology in a Colombian study population, using a genotyping array of immune-related single nucleotide polymorphisms (SNPs). Two synonymous SNPs (rs6061243 and rs6587239) were associated with progression of premalignant gastric lesions in a dominant-effects model after correction for multiple comparisons (p = 2.63E-07 and p = 7.97E-07, respectively); effect sizes were β = -0.863 and β = -0.815, respectively, where β is an estimate of effect on histopathology scores, which ranged from 1 (normal) to 5 (dysplasia). In our replication cohort, a second Colombian population, both SNPs were associated with histopathology when additively modeled (β = -0.256, 95 % CI = -0.47, -0.039; and β = -0.239, 95 % CI = -0.45, -0.024), and rs6587239 was significantly associated in a dominant-effects model (β = -0.330, 95 % CI = -0.66, 0.00). Because promoter methylation of GATA5 has previously been associated with gastric cancer, we also tested for the association of methylation status with more advanced histopathology scores in our samples and found a significant relationship (p = 0.001). A multivariate regression model revealed that the effects of both the promoter methylation and the exonic SNPs in GATA5 were independent. A SNP-by-methylation interaction term was also significant. This interaction between GATA5 variants and GATA5 promoter methylation indicates that the association of either factor with gastric disease progression is modified by the other.

Gastric adenocarcinoma microRNA profiles in fixed tissue and in plasma reveal cancer-associated and Epstein-Barr virus-related expression patterns

MicroRNA expression in formalin-fixed paraffin-embedded tissue (FFPE) or plasma may add value for cancer management. The GastroGenus miR Panel was developed to measure 55 cancer-specific human microRNAs, Epstein-Barr virus (EBV)-encoded microRNAs, and controls. This Q-rtPCR panel was applied to 100 FFPEs enriched for adenocarcinoma or adjacent non-malignant mucosa, and to plasma of 31 patients. In FFPE, microRNAs upregulated in malignant versus adjacent benign gastric mucosa were hsa-miR-21, -155, -196a, -196b, -185, and -let-7i. Hsa-miR-18a, 34a, 187, -200a, -423-3p, -484, and -744 were downregulated. Plasma of cancer versus non-cancer controls had upregulated hsa-miR-23a, -103, and -221 and downregulated hsa-miR-378, -346, -486-5p, -200b, -196a, -141, and -484. EBV-infected versus uninfected cancers expressed multiple EBV-encoded microRNAs, and concomitant dysregulation of four human microRNAs suggests that viral infection may alter cellular biochemical pathways. Human microRNAs were dysregulated between malignant and benign gastric mucosa and between plasma of cancer patients and non-cancer controls. Strong association of EBV microRNA expression with known EBV status underscores the ability of microRNA technology to reflect disease biology. Expression of viral microRNAs in concert with unique human microRNAs provides novel insights into viral oncogenesis and reinforces the potential for microRNA profiles to aid in classifying gastric cancer subtypes. Pilot studies of plasma suggest the potential for a noninvasive addition to cancer diagnostics.

Initial US evaluation of second-generation capsule colonoscopy for detecting colon polyps

Objectives

Capsule colonoscopy is an additional screening modality for colorectal cancer. Second-generation capsule colonoscopy (CC2) may have improved efficacy in the detection of colon adenomas as compared with prior devices. The purpose of this study was to evaluate the performance of CC2 in the detection of polyps in symptomatic and screening patients in the USA.

Design

Prospective, multicentre study.

Setting and participants

Two academic medical centres and two private practice facilities, evaluating patients with indications for colonoscopy.

Methods

Patients underwent capsule colonoscopy procedure using magnesium citrate as a boost, followed by colonoscopy on the same day. The main outcome measurement was accuracy of CC2 for the detection of colorectal polyps ≥6 and ≥10 mm as compared with conventional colonoscopy.

Results

51 patients were enrolled, 50 of whom had CC2 and colonoscopy examinations and were included in the accuracy analysis. 30% and 14% of patients had polyps ≥6 and ≥10 mm, respectively. For lesions ≥10 mm identified on conventional colonoscopy, CC2 sensitivity was 100% (95% CI 56.1% to 100%) with a specificity of 93.0% (79.9% to 98.2%). For polyps ≥6 mm, the CC2 sensitivity was 93.3% (66.0% to 99.7%) and the specificity was 80.0% (62.5% to 90.9%). There was a 61% adequate cleansing rate with 64% of CC2 procedures being complete.

Conclusions

In the initial US experience with CC2 there was adequate sensitivity for detecting patients with polyps ≥6 mm in size. Magnesium citrate was inadequate as a boost agent.

Trial registration number

NCT01087528.

The descriptive epidemiology of gastric cancer in Central America and comparison with United States Hispanic populations

PURPOSE

The aims of this study were to delineate the epidemiology of gastric adenocarcinoma in Central America and contrast it with Hispanic-Latino populations in the USA.

METHODS

Published literature and Central America Ministry of Health databases were used as primary data sources, including national, population-based, and hospital-based registries. US data was obtained from the National Cancer Institute (NCI)-Epidemiology End Results Program (SEER) registry. Incident gastric adenocarcinoma cases were analyzed for available data between 1985 and 2011, including demographic variables and pathology information.

RESULTS

In Central America, 19,741 incident gastric adenocarcinomas were identified. Two thirds of the cases were male, 20.5 % were under age 55, and 58.5 %were from rural areas. In the SEER database (n = 7871), 57.8 % were male and 28.9 % were under age 55. Among the US Hispanics born in Central America with gastric cancer (n = 1210), 50.3 % of cases were male and 38.1 % were under age 55. Non-cardia gastric cancer was more common in Central America (83.3 %), among US Hispanics (80.2 %), and Hispanics born in Central America (86.3 %). Cancers of the antrum were more common in Central America (73.6 %), whereas cancers of the corpus were slightly more common among US Hispanics (54.0 %). Adenocarcinoma of the diffuse subtype was relatively common, both in Central America (35.7 %) and US Hispanics (69.5 %), although Lauren classification was reported in only 50 % of cases.

CONCLUSIONS

A significant burden of gastric adenocarcinoma is observed in Central America based upon limited available data. Differences are noted between Central America and US Hispanics. Strengthening population-based registries is needed for improved cancer control in Central America, which may have implications for the growing US Hispanic population.

Association of 4p14 TLR locus with antibodies to Helicobacter pylori

A genome-wide association study among Europeans related polymorphisms of the Toll-like receptor (TLR) locus at 4p14 and the Fcγ receptor 2a locus at 1q23.3 to Helicobacter pylori serologic status. We replicated associations of 4p14 but not 1q23.3 with anti-Helicobacter pylori antibodies in 1402 Finnish males. Importantly, our analysis clarified that the phenotype affected by 4p14 is quantitative level of these antibodies rather than association with seropositivity per se. In addition, we annotated variants at 4p14 as expression quantitative trait loci (eQTL) associated with TLR6/10 and FAM114A1. Our findings suggest that 4p14 polymorphisms are linked to host immune response to H. pylori infection but not to its acquisition.

Increased Helicobacter pylori-associated gastric cancer risk in the Andean region of Colombia is mediated by spermine oxidase

Helicobacter pylori infection causes gastric cancer, the third leading cause of cancer death worldwide. More than half of the world's population is infected, making universal eradication impractical. Clinical trials suggest that antibiotic treatment only reduces gastric cancer risk in patients with non-atrophic gastritis (NAG), and is ineffective once preneoplastic lesions of multifocal atrophic gastritis (MAG) and intestinal metaplasia (IM) have occurred. Therefore, additional strategies for risk stratification and chemoprevention of gastric cancer are needed. We have implicated polyamines, generated by the rate-limiting enzyme ornithine decarboxylase (ODC), in gastric carcinogenesis. During H. pylori infection, the enzyme spermine oxidase (SMOX) is induced, which generates hydrogen peroxide from the catabolism of the polyamine spermine. Herein, we assessed the role of SMOX in the increased gastric cancer risk in Colombia associated with the Andean mountain region when compared with the low-risk region on the Pacific coast. When cocultured with gastric epithelial cells, clinical strains of H. pylori from the high-risk region induced more SMOX expression and oxidative DNA damage, and less apoptosis than low-risk strains. These findings were not attributable to differences in the cytotoxin-associated gene A oncoprotein. Gastric tissues from subjects from the high-risk region exhibited greater levels of SMOX and oxidative DNA damage by immunohistochemistry and flow cytometry, and this occurred in NAG, MAG and IM. In Mongolian gerbils, a prototype colonizing strain from the high-risk region induced more SMOX, DNA damage, dysplasia and adenocarcinoma than a colonizing strain from the low-risk region. Treatment of gerbils with either α-difluoromethylornithine, an inhibitor of ODC, or MDL 72527 (N(1),N(4)-Di(buta-2,3-dien-1-yl)butane-1,4-diamine dihydrochloride), an inhibitor of SMOX, reduced gastric dysplasia and carcinoma, as well as apoptosis-resistant cells with DNA damage. These data indicate that aberrant activation of polyamine-driven oxidative stress is a marker of gastric cancer risk and a target for chemoprevention.

A population-based study of prevalence and risk factors of chronic kidney disease in León, Nicaragua

Background

Recent studies have shown an excess of chronic kidney disease (CKD) among younger adult males in the Pacific coastal region of Nicaragua and suggest a non-conventional CKD etiology in this region. These studies have been conducted in small, non-representative populations.

Objectives

We conducted a large population-based cross-sectional study to estimate CKD prevalence in León, Nicaragua, and to evaluate the association between previously investigated risk factors and CKD.

Methods

Estimated glomerular filtration rate, derived using the MDRD equation, was assessed to determine CKD status of 2275 León residents. Multivariable logistic regression was used to estimate adjusted prevalence odds ratios. León CKD prevalence was also standardized to the demographic distributions of the León Health and Demographic Surveillance System and the León 2005 Census.

Results

CKD prevalence was 9.1%; twice as high for males (13.8%) than females (5.8%). In addition to gender, older age, rural zone, lower education level, and self-reported high blood pressure, more years of agricultural work, lija (unregulated alcohol) consumption, and higher levels of daily water consumption were significantly associated with CKD. Notably, self-reported diabetes was associated with CKD in adjusted models for females but not males.

Conclusions

Our findings are comparable to those found in regional studies and further support the hypothesis of a Mesoamerican Nephropathy.

Electronic supplementary material

The online version of this article (doi:10.1186/s40697-015-0041-1) contains supplementary material, which is available to authorized users.

A platform for gastric cancer screening in low- and middle-income countries

Gastric cancer is the second leading cause of cancer death worldwide and screening programs have had a significant impact on reducing mortality. The majority of cases occur in low- and middle-income countries (LMIC), where endoscopy resources are traditionally limited. In this paper, we introduce a platform designed to enable inexpensive gastric screening to take place in remote areas of LMIC. The system consists of a swallowable endoscopic capsule connected to an external water distribution system by a multichannel soft tether. Pressurized water is ejected from the capsule to orient the view of the endoscopic camera. After completion of a cancer screening procedure, the outer shell of the capsule and the soft tether can be disposed, while the endoscopic camera is reclaimed without needing further reprocessing. The capsule, measuring 12 mm in diameter and 28 mm in length, is able to visualize the inside of the gastric cavity by combining waterjet actuation and the adjustment of the tether length. Experimental assessment was accomplished through a set of bench trials, ex vivo analysis, and in vivo feasibility validation. During the ex vivo trials, the platform was able to visualize the main landmarks that are typically observed during a gastric cancer screening procedure in less than 8 min. Given the compact footprint, the minimal cost of the disposable parts, and the possibility of running on relatively available and inexpensive resources, the proposed platform can potentially widen gastric cancer screening programs in LMIC.

Molecular oncology testing in resource-limited settings

Cancer prevalence and mortality are high in developing nations, where resources for cancer control are inadequate. Nearly one-quarter of cancers in resource-limited nations are infection related, and molecular assays can capitalize on this relationship by detecting pertinent pathogen genomes and human gene variants to identify those at highest risk for progression to cancer, to classify lesions, to predict effective therapy, and to monitor tumor burden over time. Prime examples are human papillomavirus in cervical neoplasia, Helicobacter pylori and Epstein-Barr virus in gastric adenocarcinoma and lymphoma, and hepatitis B or C virus in hepatocellular cancer. Research is underway to engineer devices that overcome social, economic, and technical barriers limiting effective laboratory support. Additional challenges include an educated workforce, infrastructure for quality metrics and record keeping, and funds to sustain molecular test services. The combination of well-designed interfaces, novel and robust electrochemical technology, and telemedicine tools will promote adoption by frontline providers. Fast turnaround is crucial for surmounting loss to follow-up, although increased use of cell phones, even in rural areas, enhances options for patient education and engagement. Links to a broadband network facilitate consultation and centralized storage of medical data. Molecular technology shows promise to address gaps in health care through rapid, user-friendly, and cost-effective devices reflecting clinical priorities in resource-poor areas.

Activation of EGFR and ERBB2 by Helicobacter pylori results in survival of gastric epithelial cells with DNA damage

BACKGROUND & AIMS

The gastric cancer-causing pathogen Helicobacter pylori up-regulates spermine oxidase (SMOX) in gastric epithelial cells, causing oxidative stress-induced apoptosis and DNA damage. A subpopulation of SMOX(high) cells are resistant to apoptosis, despite their high levels of DNA damage. Because epidermal growth factor receptor (EGFR) activation can regulate apoptosis, we determined its role in SMOX-mediated effects.

METHODS

SMOX, apoptosis, and DNA damage were measured in gastric epithelial cells from H. pylori-infected Egfr(wa5) mice (which have attenuated EGFR activity), Egfr wild-type mice, or in infected cells incubated with EGFR inhibitors or deficient in EGFR. A phosphoproteomic analysis was performed. Two independent tissue microarrays containing each stage of disease, from gastritis to carcinoma, and gastric biopsy specimens from Colombian and Honduran cohorts were analyzed by immunohistochemistry.

RESULTS

SMOX expression and DNA damage were decreased, and apoptosis increased in H. pylori-infected Egfr(wa5) mice. H. pylori-infected cells with deletion or inhibition of EGFR had reduced levels of SMOX, DNA damage, and DNA damage(high) apoptosis(low) cells. Phosphoproteomic analysis showed increased EGFR and erythroblastic leukemia-associated viral oncogene B (ERBB)2 signaling. Immunoblot analysis showed the presence of a phosphorylated (p)EGFR-ERBB2 heterodimer and pERBB2; knockdown of ErbB2 facilitated apoptosis of DNA damage(high) apoptosis(low) cells. SMOX was increased in all stages of gastric disease, peaking in tissues with intestinal metaplasia, whereas pEGFR, pEGFR-ERBB2, and pERBB2 were increased predominantly in tissues showing gastritis or atrophic gastritis. Principal component analysis separated gastritis tissues from patients with cancer vs those without cancer. pEGFR, pEGFR-ERBB2, pERBB2, and SMOX were increased in gastric samples from patients whose disease progressed to intestinal metaplasia or dysplasia, compared with patients whose disease did not progress.

CONCLUSIONS

In an analysis of gastric tissues from mice and patients, we identified a molecular signature (based on levels of pEGFR, pERBB2, and SMOX) for the initiation of gastric carcinogenesis.

Case-case comparison of smoking and alcohol risk associations with Epstein-Barr virus-positive gastric cancer

Helicobacter pylori is the primary cause of gastric cancer. However, monoclonal Epstein-Barr virus (EBV) nucleic acid is also present in up to 10% of these tumors worldwide. EBV prevalence is increased with male sex, nonantral localization and surgically disrupted anatomy. To further examine associations between EBV and gastric cancer, we organized an international consortium of 11 studies with tumor EBV status assessed by in situ hybridization. We pooled individual-level data on 2,648 gastric cancer patients, including 184 (7%) with EBV-positive cancers; all studies had information on cigarette use (64% smokers) and nine had data on alcohol (57% drinkers). We compared patients with EBV-positive and EBV-negative tumors to evaluate smoking and alcohol interactions with EBV status. To account for within-population clustering, multilevel logistic regression models were used to estimate interaction odds ratios (OR) adjusted for distributions of sex (72% male), age (mean 59 years), tumor histology (56% Lauren intestinal-type), anatomic subsite (61% noncardia) and year of diagnosis (1983-2012). In unadjusted analyses, the OR of EBV positivity with smoking was 2.2 [95% confidence interval (CI) 1.6-3.2]. The OR was attenuated to 1.5 (95% CI 1.01-2.3) by adjustment for the possible confounders. There was no significant interaction of EBV status with alcohol drinking (crude OR 1.4; adjusted OR 1.0). Our data indicate the smoking association with gastric cancer is stronger for EBV-positive than EBV-negative tumors. Conversely, the null association with alcohol does not vary by EBV status. Distinct epidemiologic characteristics of EBV-positive cancer further implicate the virus as a cofactor in gastric carcinogenesis.

Community diarrhea incidence before and after rotavirus vaccine introduction in Nicaragua

We estimated the incidence of watery diarrhea in the community before and after introduction of the pentavalent rotavirus vaccine in León, Nicaragua. A random sample of households was selected before and after rotavirus vaccine introduction. All children < 5 years of age in selected households were eligible for inclusion. Children were followed every 2 weeks for watery diarrhea episodes. The incidence rate was estimated as numbers of episodes per 100 child-years of exposure time. A mixed effects Poisson regression model was fit to compare incidence rates in the pre-vaccine and vaccine periods. The pre-vaccine cohort (N = 726) experienced 36 episodes per 100 child-years, and the vaccine cohort (N = 826) experienced 25 episodes per 100 child-years. The adjusted incidence rate ratio was 0.60 (95% confidence interval [CI] 0.40, 0.91) during the vaccine period versus the pre-vaccine period, indicating a lower incidence of watery diarrhea in the community during the vaccine period.

A multicenter, U.S. experience of single-balloon, double-balloon, and rotational overtube-assisted enteroscopy ERCP in patients with surgically altered pancreaticobiliary anatomy (with video)

BACKGROUND

Data on overtube-assisted enteroscopy to facilitate ERCP in patients with surgically altered pancreaticobiliary anatomy, or long-limb surgical bypass, is limited.

OBJECTIVE

To evaluate and compare ERCP success by using single-balloon (SBE), double-balloon (DBE), or rotational overtube enteroscopy.

DESIGN

Consecutive patients identified retrospectively.

SETTING

Eight U.S. referral centers.

PATIENTS

Long-limb surgical bypass patients with suspected pancreaticobiliary diseases.

INTERVENTION

Overtube-assisted enteroscopy ERCP.

MAIN OUTCOME MEASUREMENTS

Enteroscopy success: visualizing the pancreaticobiliary-enteric anastomosis or papilla. ERCP success: completing the intended pancreaticobiliary intervention. Clinical success: greater than 50% reduction in abdominal pain or level of hepatic enzyme elevations or resolution of jaundice.

RESULTS

From January 2008 through October 2009, 129 patients had 180 enteroscopy-ERCPs. Anatomy was Roux-en-Y: gastric bypass (n = 63), hepaticojejunostomy (n = 45), postgastrectomy (n = 6), Whipple procedure (n = 10), and other (n = 5). ERCP success was 81 of 129 (63%). Enteroscopy success: 92 of 129 (71%), of whom 81 of 92 (88%) achieved ERCP success. Reasons for ERCP failure (n = 48): afferent limb entered but pancreaticobiliary anastomosis and/or papilla not reached (n = 23), cannulation failure (n = 11), afferent limb angulation (n = 8), and jejunojejunostomy not identified (n = 6). Select interventions: anastomotic stricturoplasty (cautery ± dilation, n = 16), stone removal (n = 21), stent (n = 25), and direct cholangioscopy (n = 11). ERCP success rates were similar between Roux-en-Y gastric bypass and other long-limb surgical bypass and among SBE, DBE, and rotational overtube enteroscopy. Complications were 16 of 129, 12.4%.

LIMITATIONS

Retrospective study.

CONCLUSION

(1) ERCP is successful in nearly two-thirds of long-limb surgical bypass patients and in 88% when the papilla or pancreaticobiliary-enteric anastomosis is reached. (2) Enteroscopy success in long-limb surgical bypass is similar among SBE, DBE, and rotational overtube enteroscopy methods. (3) Referral of long-limb surgical bypass patients who require ERCP to high-volume institutions may be considered before more invasive percutaneous or surgical alternatives.

Risk of recurrent Helicobacter pylori infection 1 year after initial eradication therapy in 7 Latin American communities

IMPORTANCE

The long-term effectiveness of Helicobacter pylori eradication programs for preventing gastric cancer will depend on recurrence risk and individual and community factors.

OBJECTIVE

To estimate risk of H. pylori recurrence and assess factors associated with successful eradication 1 year after treatment.

DESIGN, SETTING, AND PARTICIPANTS

Cohort analysis of 1463 randomized trial participants aged 21 to 65 years from 7 Latin American communities, who were treated for H. pylori and observed between September 2009 and July 2011.

INTERVENTIONS

Randomization to 1 of 3 treatment groups: 14-day lansoprazole, amoxicillin, and clarithromycin (triple therapy); 5-day lansoprazole and amoxicillin followed by 5-day lansoprazole, clarithromycin, and metronidazole (sequential); or 5-day lansoprazole, amoxicillin, clarithromycin, and metronidazole (concomitant). Participants with a positive (13)C-urea breath test (UBT) 6 to 8 weeks posttreatment were offered voluntary re-treatment with 14-day bismuth-based quadruple therapy.

MEASUREMENTS

Recurrent infection after a negative posttreatment UBT and factors associated with successful eradication at 1-year follow-up.

RESULTS

Among participants with UBT-negative results who had a 1-year follow-up UBT (n=1091), 125 tested UBT positive, a recurrence risk of 11.5% (95% CI, 9.6%-13.5%). Recurrence was significantly associated with study site (P = .03), nonadherence to initial therapy (adjusted odds ratio [AOR], 2.94; 95% CI, 1.31-6.13; P = .01), and children in the household (AOR, 1.17; 95% CI, 1.01-1.35 per child; P = .03). Of the 281 with positive posttreatment UBT results, 138 completed re-treatment, of whom 93 tested UBT negative at 1 year. Among the 1340 who had a 1-year UBT, 80.4% (95% CI, 76.4%-83.9%), 79.8% (95% CI, 75.8%-83.5%), and 77.8% (95% CI, 73.6%-81.6%) had UBT-negative results in the triple, sequential, and concomitant groups, respectively (P = .61), with 79.3% overall effectiveness (95% CI, 77.1%-81.5%). In a single-treatment course analysis that ignored the effects of re-treatment, the percentage of UBT-negative results at 1 year was 72.4% (95% CI, 69.9%-74.8%) and was significantly associated with study site (P < .001), adherence to initial therapy (AOR, 0.26; 95% CI, 0.15-0.42; P < .001), male sex (AOR, 1.63; 95% CI, 1.25-2.13; P < .001), and age (AOR, 1.14; 95% CI, 1.02-1.27 per decade; P = .02). One-year effectiveness among all 1463 enrolled participants, considering all missing UBT results as positive, was 72.7% (95% CI, 70.3%-74.9%).

CONCLUSIONS AND RELEVANCE

One year after treatment for H. pylori infection, recurrence occurred in 11.5% of participants who had negative posttreatment UBT results. Recurrence determinants (ie, nonadherence and demographics) may be as important as specific antibiotic regimen in determining the long-term success of H. pylori eradication interventions. Study findings are relevant to the feasibility of programs for the primary prevention of gastric cancer in high-incidence regions of Latin America.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01061437.

Gastric cancer incidence estimation in a resource-limited nation: use of endoscopy registry methodology

PURPOSE

Cancer epidemiology is challenging in developing nations, in the absence of reliable pathology-based cancer registries. Clinical experience suggests that the incidence of gastric cancer is high in Honduras, in contrast to the limited available national statistics at the time of study initiation (IARC GLOBOCAN 2002: males 15.2, females 10.8). We estimate the incidence of gastric cancer for Honduras using an endoscopy registry as a complimentary resource.

METHODS

We conducted a retrospective analysis of incident noncardia gastric adenocarcinoma cases in western Honduras for the period 2000-2009. This region is well circumscribed geopolitically with a single district hospital and established referral patterns, to provide a unique epidemiological niche to facilitate estimation of incidence rates. A prospective, comprehensive database of all endoscopy procedures from this hospital was utilized at the primary data source. The catchment area for gastroenterology services for the at-risk population was validated by calculating the overall endoscopy utilization rates for each municipality in western Honduras. Incident cases of gastric adenocarcinoma were determined by the endoscopic diagnosis. Pathology services are not financed by the Ministry of Health, and histology data were incorporated when available. Population statistics were obtained from the Honduras National Statistics Institute (INE). Age-standardized incidence rates (ASIRs) were calculated using world standard population fractions.

RESULTS

The catchment area for western Honduras was validated with the municipality threshold of 30 endoscopies per 10(6) person-years, with inclusion of a total of 40 municipalities. In the western Honduras catchment area, there were 670 incident cases (439 M, 231 F) of noncardia gastric adenocarcinoma during the study decade 2000-2009. Notably, 67 (10.0 %) and 165 (24.6 %) of cases were under the ages of 45 and 55, respectively. The case-finding rate was 5.1 endoscopies performed for each new diagnosis of gastric cancer. The ASIRs for the decade were 30.8 for males and 13.9 for females. Clinically, 60.3 % of gastric cancers were Borrmann type 3 (ulcerated mass), and evidence of advanced disease with pyloric obstruction was common (35.2 %). Subtypes by the Lauren classification were distributed among diffuse (56 %), intestinal (34 %), and indeterminate (9.9 %), in subjects with available pathology (526/670).

CONCLUSIONS

The endoscopy procedure registry may serve as a complimentary data resource for gastric cancer incidence estimation in resource-limited nation settings wherein pathology services and cancer registries are absent. The results remain an underestimation in this setting due to the challenges of access to care and related factors. The methodology helps to more fully characterize the high incidence of gastric cancer in western Honduras and this region of Central America and demonstrate the need for additional epidemiology research, and interventions focused on prevention and treatment.

Iron deficiency accelerates Helicobacter pylori-induced carcinogenesis in rodents and humans

Gastric adenocarcinoma is strongly associated with Helicobacter pylori infection; however, most infected persons never develop this malignancy. H. pylori strains harboring the cag pathogenicity island (cag+), which encodes CagA and a type IV secretion system (T4SS), induce more severe disease outcomes. H. pylori infection is also associated with iron deficiency, which similarly augments gastric cancer risk. To define the influence of iron deficiency on microbial virulence in gastric carcinogenesis, Mongolian gerbils were maintained on iron-depleted diets and infected with an oncogenic H. pylori cag+ strain. Iron depletion accelerated the development of H. pylori-induced premalignant and malignant lesions in a cagA-dependent manner. H. pylori strains harvested from iron-depleted gerbils or grown under iron-limiting conditions exhibited enhanced virulence and induction of inflammatory factors. Further, in a human population at high risk for gastric cancer, H. pylori strains isolated from patients with the lowest ferritin levels induced more robust proinflammatory responses compared with strains isolated from patients with the highest ferritin levels, irrespective of histologic status. These data demonstrate that iron deficiency enhances H. pylori virulence and represents a measurable biomarker to identify populations of infected persons at high risk for gastric cancer.

Iron deficiency accelerates Helicobacter pylori-induced carcinogenesis in rodents and humans

Gastric adenocarcinoma is strongly associated with Helicobacter pylori infection; however, most infected persons never develop this malignancy. H. pylori strains harboring the cag pathogenicity island (cag+), which encodes CagA and a type IV secretion system (T4SS), induce more severe disease outcomes. H. pylori infection is also associated with iron deficiency, which similarly augments gastric cancer risk. To define the influence of iron deficiency on microbial virulence in gastric carcinogenesis, Mongolian gerbils were maintained on iron-depleted diets and infected with an oncogenic H. pylori cag+ strain. Iron depletion accelerated the development of H. pylori-induced premalignant and malignant lesions in a cagA-dependent manner. H. pylori strains harvested from iron-depleted gerbils or grown under iron-limiting conditions exhibited enhanced virulence and induction of inflammatory factors. Further, in a human population at high risk for gastric cancer, H. pylori strains isolated from patients with the lowest ferritin levels induced more robust proinflammatory responses compared with strains isolated from patients with the highest ferritin levels, irrespective of histologic status. These data demonstrate that iron deficiency enhances H. pylori virulence and represents a measurable biomarker to identify populations of infected persons at high risk for gastric cancer.

Epidemiology of Helicobacter pylori infection in six Latin American countries (SWOG Trial S0701)

OBJECTIVE

To investigate the potential determinants of Helicobacter pylori infection between adults 21-65 years old.

METHODS

Data are from the initial screening visit of a randomized clinical trial of three antibiotic regimens to eradicate H. pylori, conducted in seven sites (Santiago-Chile, Túquerres-Colombia, Guanacaste-Costa Rica, Copán-Honduras, Obregón and Tapachula-México, León-Nicaragua). Thousand eight hundred and fifty-nine adults from the general population were screened for H. pylori infection using an urea breath test (UBT) and were interviewed to assess socioeconomic-, demographic-, and symptom-related characteristics. Logistic regression was used to assess the relationship between these characteristics and H. pylori positivity at enrollment.

RESULTS

Among the 1,852 eligible participants for whom a conclusive UBT result was obtained, H. pylori prevalence was 79.4 %, ranging from 70.1 to 84.7 % among the seven centers. Prevalence did not differ by sex (female: 78.4, male: 80.9; p = 0.20) or age (p = 0.08). H. pylori positivity increased with increasing number of siblings (p trend <0.0001). Participants with education beyond 12 years were less likely to be UBT-positive (OR 0.4: 0.3-0.6, compared to participants with 0-6 years of schooling) as were those employed outside the home (OR 0.7: 0.6-1.0). Odds of H. pylori infection increased with the presence of certain living conditions during childhood including having lived in a household with an earth floor (OR 1.8: 1.4-2.4), lack of indoor plumbing (OR 1.3: 1.0-1.8) and crowding (OR 1.4: 1.0-1.8, for having more than two persons per bedroom). Regarding current household conditions, living with more than 3 children in the household (OR 1.7: 1.2-2.5) and crowding (OR 1.8: 1.3-2.3) were associated with H. pylori infection.

CONCLUSIONS

The prevalence of H. pylori in adults was high and differed significantly among the six Latin American countries studied (p < 0.001). Our findings confirm the strong link between poor socioeconomic conditions and H. pylori infection.