Colorectal Cancer Screening Programs in Latin America: A Systematic Review and Meta-Analysis

Importance

Colorectal cancer (CRC) is a leading cause of cancer-related mortality globally, with increasing incidence and mortality in Latin America. CRC screening programs can reduce disease burden, but information on screening programs in Latin America is limited.

Objective

To describe characteristics (eg, type of program, uptake, neoplastic yield) of CRC screening programs in Latin America.

Data Sources

PubMed, Ovid MEDLINE, EMBASE, Cochrane, PsycINFO, Web of Science Core Collection, LILACS, and SciELO were searched from inception to February 2023. Relevant references from bibliographies, conference proceedings, and gray literature were considered. The search strategy included English, Spanish, and Portuguese terms.

Study Selection

Included were studies of CRC screening programs in Latin America using fecal immunochemical test (FIT) or colonoscopy as the primary screening method. Four reviewers independently assessed study eligibility based on titles, with review of abstracts and full texts as needed.

Data Extraction and Synthesis

Guidelines from Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed for data abstraction and quality assessment. Descriptive information was extracted, and data were pooled using a random-effects model.

Main outcomes and Measures

Program performance indicators included rates of participation and FIT positivity, adenoma detection rate (ADR), advanced adenoma detection rate (AADR), CRC detection rate, and colonoscopy quality indicators.

Results

There were 17 studies included from upper middle-income and high-income countries in Latin America with a total of 123 929 participants. Thirteen studies used FIT as the initial screening method, whereas 4 used screening colonoscopy. The participation rate in FIT-based programs was 85.8% (95% CI, 78.5%-91.4%). FIT positivity rates were 15.2% (95% CI, 9.6%-21.8%) for the 50-ng/mL threshold and 9.7% (95% CI, 6.8%-13.0%) for the 100-ng/mL threshold. For FIT-based studies, the pooled ADR was 39.0% (95% CI, 29.3%-49.2%) and CRC detection rate was 4.9% (95% CI, 2.6%-7.9%); for screening colonoscopy-based studies, the pooled ADR was 19.9% (95% CI, 15.5%-24.8%) and CRC detection rate was 0.4% (95% CI, 0.1%-0.8%).

Conclusions and Relevance

This systematic review and meta-analysis suggests that CRC screening in upper middle-income countries in Latin America is feasible, detecting rates of neoplasia comparable with those of high-income regions. Population-based screening programs should be developed or enhanced in these settings. There is a knowledge gap regarding feasibility and yield of screening programs in lower middle-income countries.

Gastric coinfection with thiopeptide-positive Cutibacterium acnes decreases FOXM1 and pro-inflammatory biomarker expression in a murine model of Helicobacter pylori-induced gastric cancer

IMPORTANCE

H. pylori infects half of the world population and is the leading cause of gastric cancer. We previously demonstrated that gastric cancer risk is associated with gastric microbiota. Specifically, gastric urease-positive Staphylococcus epidermidis and Streptococcus salivarius had contrasting effects on H. pylori-associated gastric pathology and immune responses in germ-free INS-GAS mice. As gastritis progresses to gastric cancer, the oncogenic transcription factor Foxm1 becomes increasingly expressed. In this study, we evaluated the gastric commensal C. acnes, certain strains of which produce thiopeptides that directly inhibit FOXM1. Thiopeptide-positive C. acnes was isolated from Nicaraguan patient gastric biopsies and inoculated into germ-free INS-GAS mice with H. pylori. We, therefore, asked whether coinfection with C. acnes expressing thiopeptide and H. pylori would decrease gastric Foxm1 expression and pro-inflammatory cytokine mRNA and protein levels. Our study supports the growing literature that specific non-H. pylori gastric bacteria affect inflammatory and cancer biomarkers in H. pylori pathogenesis.

Wood cookstove use is associated with gastric cancer in Central America and mediated by host genetics

Biomass cookstove food preparation is linked to aero-digestive cancers, mediated by ingested and inhaled carcinogens (e.g., heterocyclic amines, and polycyclic aromatic hydrocarbons). We investigated the association between gastric adenocarcinoma, wood cookstove use, H. pylori CagA infection and risk modification by variants in genes that metabolize and affect the internal dose of carcinogens. We conducted a population-based, case-control study (814 incident cases, 1049 controls) in rural Honduras, a high-incidence region with a homogeneous diet and endemic H. pylori infection, primarily with the high-risk CagA genotype. We investigated factors including wood cookstove use, H. pylori CagA serostatus, and 15 variants from 7 metabolizing genes, and the interactions between wood stove use and the genetic variants. Male sex (OR 2.0, 1.6-2.6), age (OR 1.04, 1.03-1.05), wood cookstove use (OR 2.3, 1.6-3.3), and CagA serostatus (OR 3.5, 2.4-5.1) and two SNPs in CYP1B1 (rs1800440 and rs1056836) were independently associated with gastric cancer in multivariate analysis. In the final multivariate model, a highly significant interaction (OR 3.1, 1.2-7.8) was noted between wood cookstove use and the rs1800440 metabolizing genotype, highlighting an important gene-environment interaction. Lifetime wood cookstove use associates with gastric cancer risk in the high-incidence regions of Central America, and the association is dependent on the rs1800440 genotype in CYP1B1. H. pylori CagA infection, wood cookstove use and the rs1800440 genotype, all of which are highly prevalent, informs who is at greatest risk from biomass cookstove use.

Gastric Cancer: Emerging Trends in Prevention, Diagnosis, and Treatment

Gastric adenocarcinoma (GC) is the fourth leading cause of global cancer mortality, and the leading infection-associated cancer. Helicobacter pylori is the dominant risk factor for GC and classified as an IARC class I carcinogen. Surveillance of gastric premalignant conditions is now indicated in high-risk patients. Upper endoscopy is the gold standard for GC diagnosis, and image-enhanced endoscopy increases the detection of gastric premalignant conditions and early gastric cancer (EGC). Clinical staging is crucial for treatment approach, defining early gastric cancer, operable locoregional disease, and advanced GC. Endoscopic submucosal dissection is the treatment of choice for most EGC. Targeted therapies are rapidly evolving, based on biomarkers including MSI/dMMR, HER2, and PD-L1. These advancements in surveillance, diagnostic and therapeutic strategies are expected to improve GC survival rates in the near term.

Racial/ethnic disparities in gastric cancer: A 15-year population-based analysis

BACKGROUND AND AIMS

Disparities in gastric cancer incidence and mortality have been reported among ethnic/racial groups. While gastric cancer is not common in the U.S., it is among the top 10 causes of cancer-related death among Hispanics living in Puerto Rico (PRH). This study compared gastric cancer incidence rates during a 15-year period (2002-2006, 2007-2011, and 2012-2016) between PRH and racial/ethnic groups in the mainland U.S., including Non-Hispanic Whites (NHW), Non-Hispanics Blacks (NHB), Hispanics (USH), and Non-Hispanic Asian or Pacific Islanders (NHAPI).

METHODS

Primary gastric cancer cases (ICD-O-3 codes C16.0 to C16.9) from the Puerto Rico Central Cancer Registry and SEER diagnosed from January 1, 2002 to December 31, 2016 were included in the analysis. The Joinpoint Regression Program and standardized rate ratios were used to estimate Annual Percent Changes (APC) and differences in gastric cancer incidence among racial/ethnic groups, respectively.

RESULTS

Our analysis included 83,369 gastric cancer cases (PRH n = 4202; NHW n = 43,164; NHB n = 10,414; NHAPI n = 11,548; USH n = 14,041). USH had the highest number of cases among individuals <50 years, whereas NHW and PRH had the highest percentage among individuals ≥50 years. PRH and USH were the only groups with increasing APCs among individuals <50 years.

CONCLUSIONS

Gastric cancer continues to be a common cancer among PRH, despite the overall decrease in incidence among other racial/ethnic groups. Studies evaluating the gastric cancer risk factors among high-risk groups are necessary to establish health policy and modify gastric cancer screening algorithms among Hispanics.

Western Honduras Copán Population-Based Cancer Registry: Initial Estimates and a Model for Rural Central America

PURPOSE

Population-based cancer registries (PBCRs) are critical for national cancer control planning, yet few low- and middle-income countries (LMICs) have quality PBCRs. The Central America Four region represents the principal LMIC region in the Western hemisphere. We describe the establishment of a PBCR in rural Western Honduras with first estimates for the 2013-2017 period.

METHODS

The Western Honduras PBCR was established through a collaboration of academic institutions and the Honduras Ministry of Health for collection of incident cancer data from public and private health services. Data were recorded using the Research Electronic Data Capture (REDCap) web-based platform with data monitoring and quality checks. Crude and age-standardized rates (ASRs) were calculated at the regional level, following WHO methodology.

RESULTS

The web-based platform for data collection, available ancillary data services (eg, endoscopy), and technical support from international centers (United States and Colombia) were instrumental for quality control. Crude cancer incidence rates were 112.2, 69.8, and 154.6 per 100,000 habitants overall, males, and females, respectively (excluding nonmelanoma skin cancer). The adjusted ASRs were 84.2, 49.6, and 118.9 per 100,000 overall habitants, males, and females, respectively. The most common sites among men were stomach (ASR 26.0, 52.4%), colorectal (ASR 5.11, 10.15%), and prostate (ASR 2.7, 5.4%). The most common sites in women were cervix (ASR 34.2, 36.7%), breast (ASR 11.2, 12.3%), and stomach (ASR 10.8, 11.7%).

CONCLUSION

The Copán-PBCR represents a successful model to develop cancer monitoring in rural LMICs. Innovations included the use of the REDCap platform and leverage of Health Ministry resources. This provides the first PBCR data for Honduras and the Central America Four and confirms that infection-driven cancers, such as gastric and cervical, should be priority targets for cancer control initiatives.

Prevalence and Associated Dietary Factors of Rome IV Functional Gastrointestinal Disorders in Rural Western Honduras

BACKGROUND

The literature is limited regarding the prevalence of functional gastrointestinal disorders (FGIDs) in Central America, and the role of dietary factors.

METHODS

The Rome IV diagnostic questionnaire and National Cancer Institute Diet History questionnaire were administered in one-on-one interviews to a distributed cross section of the general adult population of Western Honduras. Our aim was to estimate prevalence of common FGIDs and symptoms and their relationships to dietary habits.

RESULTS

In total, 815 subjects were interviewed, of whom 151 fulfilled criteria for an FGID (18.5%). Gastroduodenal FGIDs were noted in 9.4%, with epigastric pain syndrome (EPS) more common than postprandial distress syndrome, 8.5% versus 1.6%. Among bowel disorders, functional abdominal bloating (FAB) was most prevalent (6.3%), followed by irritable bowel syndrome (3.6%), functional diarrhea (FDr; 3.4%), and functional constipation (1.1%). A significant inverse association was noted between regular bean intake and any FGID (OR 0.41, 95% CI 0.27-0.63), driven by IBS and FDr. Vegetable consumption was associated with lower prevalence of functional diarrhea (OR 0.12; 95% CI 0.04-0.35) and any diarrheal disorder (OR 0.11; 95% CI 0.04-0.31). Subjects with a median daily intake of ≥ 4 corn tortillas had 1.75 (95% CI 1.22-2.50) times the odds of having any FGID.

CONCLUSIONS

FGIDs were common in this rural low-resource setting in Central America, with an intriguing distribution of specific FGIDs. EPS and FAB were common, but IBS was not. Local dietary factors were associated with specific FGIDs, suggesting that diet may play a role in global variations of FGIDs.

The Colombian Chemoprevention Trial: 20-Year Follow-Up of a Cohort of Patients With Gastric Precancerous Lesions

BACKGROUND & AIMS

Helicobacter pylori eradication and endoscopic surveillance of gastric precancerous lesions are strategies to reduce gastric cancer (GC) risk. To our knowledge, this study is the longest prospective cohort of an H pylori eradication trial in a Hispanic population.

METHODS

A total of 800 adults with precancerous lesions were randomized to anti-H pylori treatment or placebo. Gastric biopsy samples taken at baseline and 3, 6, 12, 16, and 20 years were assessed by our Correa histopathology score. A generalized linear mixed model with a participant-level random intercept was used to estimate the effect of H pylori status on the score over time. Logistic regression models were used to estimate progression by baseline diagnosis and to estimate GC risk by intestinal metaplasia (IM) subtype and anatomic location.

RESULTS

Overall, 356 individuals completed 20 years of follow-up. Anti-H pylori therapy (intention-to-treat) reduced progression of the Correa score (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.38-0.93). H pylori-negative status had a beneficial effect on the score over time (P = .036). Among individuals with IM (including indefinite for dysplasia) at baseline, incidence rates per 100 person-years were 1.09 (95% CI, 0.85-1.33) for low-grade/high-grade dysplasia and 0.14 (95% CI, 0.06-0.22) for GC. Incomplete-type (vs complete-type) IM at baseline presented higher GC risk (OR, 13.4; 95% CI, 1.8-103.8). Individuals with corpus (vs antrum-restricted) IM showed an OR of 2.1 (95% CI, 0.7-6.6) for GC.

CONCLUSIONS

In a high-GC-risk Hispanic population, anti-H pylori therapy had a long-term beneficial effect against histologic progression. Incomplete IM is a strong predictor of GC risk.

A 500-year tale of co-evolution, adaptation, and virulence: Helicobacter pylori in the Americas

Helicobacter pylori is a common component of the human stomach microbiota, possibly dating back to the speciation of Homo sapiens. A history of pathogen evolution in allopatry has led to the development of genetically distinct H. pylori subpopulations, associated with different human populations, and more recent admixture among H. pylori subpopulations can provide information about human migrations. However, little is known about the degree to which some H. pylori genes are conserved in the face of admixture, potentially indicating host adaptation, or how virulence genes spread among different populations. We analyzed H. pylori genomes from 14 countries in the Americas, strains from the Iberian Peninsula, and public genomes from Europe, Africa, and Asia, to investigate how admixture varies across different regions and gene families. Whole-genome analyses of 723 H. pylori strains from around the world showed evidence of frequent admixture in the American strains with a complex mosaic of contributions from H. pylori populations originating in the Americas as well as other continents. Despite the complex admixture, distinctive genomic fingerprints were identified for each region, revealing novel American H. pylori subpopulations. A pan-genome Fst analysis showed that variation in virulence genes had the strongest fixation in America, compared with non-American populations, and that much of the variation constituted non-synonymous substitutions in functional domains. Network analyses suggest that these virulence genes have followed unique evolutionary paths in the American populations, spreading into different genetic backgrounds, potentially contributing to the high risk of gastric cancer in the region.

Novel academic center model for Spanish-speaking patients in the southeastern United States

Latinos form the largest U.S. minority and will account for one quarter of the population by 2050. Immigration trends from 1995-2010 challenged health systems in "new destination" regions such as the southeastern U.S., with Latino population increases of 200-400%, and a minimal bilingual health workforce. Academic medical centers and safety net hospitals are challenged to respond beyond the interpreter paradigm of care delivery to provide efficient, cost-effective and compassionate care that complies with the U.S. Title VI mandates. We describe the design and successful implementation of an academic model in the care of Spanish-speaking patients in the pediatric and adult primary care and subspecialty settings in the University of North Carolina Health Care System. This model leverages a limited bilingual workforce to maximize the extent and quality of language-concordant care for this population The innovative features of the UNC Center for Latino Health (CELAH) is based upon five principles: patient navigation, a medical home, a block-scheduling system, a "virtual clinic" model using existing space, and leveraged cost-neutral resources. Patients are scheduled to specific half-day sessions in specialty clinics and matched with bilingual faculty and staff. This facilitates door-to-door care in Spanish for patients, the majority of whom are immigrants from rural Mexico and Central America with limited English and health literacy. CELAH is considered an academic transition model in anticipation of an adequate bilingual health workforce in 1-2 decades. As a hub, this clinical platform supports unique programs in medical education, translational and health equity research, community outreach, and faculty engagement.

Increased Incidence and Mortality of Gastric Cancer in Immigrant Populations from High to Low Regions of Incidence: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Gastric cancer is the leading cause of infection-related cancer death and the third-leading cause of cancer death worldwide. The effect of immigration on gastric cancer risk is not well-defined but might be helpful for screening or surveillance endeavors. We performed a systematic review and meta-analysis to define the risk of gastric cancer in immigrants from high-incidence regions to low-incidence regions (including Western Europe, Australia, Brazil, Canada, Israel, and the United States).

METHODS

We searched MEDLINE and EMBASE databases, from January 1980 to January 2019, for studies that identified immigrants from high-incidence regions of gastric cancer, provided clear definitions of immigrant and reference populations, and provided sufficient data to calculate gastric cancer incidence and gastric cancer-related mortality. We performed meta-analyses of standardized incidence ratios (SIR) for first-generation immigrants from high- to low-incidence regions, stratified by immigrant generation, sex, and anatomic and histologic subtype, when data were available.

RESULTS

We identified 38 cohort studies that met our inclusion criteria. All 13 studies of 21 distinct populations reported significantly increased SIRs for gastric cancer in first-generation foreign-born immigrants (men SIR range, 1.24-4.50 and women SIR range, 1.27-5.05). The pooled SIR for immigrants with all types of gastric cancer was 1.66 (95% CI, 1.52-1.80) for men and 1.83 (95% CI, 1.69-1.98) for women. Nine studies from 2 high-incidence populations (the former Soviet Union and Japan) reported an increased gastric cancer standardized mortality ratio in first-generation immigrants who migrated to regions of low incidence (former Soviet Union immigrants, 1.44-1.91 for men and 1.40-2.56 for women).

CONCLUSIONS

Immigrants from regions with a high incidence of gastric cancer to regions of low incidence maintain a higher risk of gastric cancer and related mortality, based on a comprehensive systematic review and meta-analysis. Assessment of immigrant generation along with other risk factors might help identify high-risk populations for prevention and therapeutic interventions.

Helicobacter pylori antimicrobial resistance and antibiotic consumption in the low-resource Central America setting

BACKGROUND

Antimicrobial resistance is a global public health problem, particularly in low- and middle-income countries (LMICs), where antibiotics are often obtained without a prescription. H. pylori antimicrobial resistance patterns are informative for patient care and gastric cancer prevention programs, have been shown to correlate with general antimicrobial consumption, and may guide antimicrobial stewardship programs in LMICs. We report H. pylori resistance and antimicrobial utilization patterns for western Honduras, representative of rural Central America.

METHODS

In the context of the western Honduras gastric cancer epidemiology initiative, gastric biopsies from 189 patients were studied for culture and resistance patterns. Antimicrobial utilization was investigated for common H. pylori treatment regimens from regional public (7 antimicrobials) and national private (4 antimicrobials) data, analyzed in accordance with WHO anatomical therapeutic chemical defined daily doses (DDD) method and expressed as DDD/1000 inhabitants per day (DID) and per year (DIY).

RESULTS

H. pylori was successfully cultured from 116 patients (56% males, mean age: 54), and nearly all strains were cagA+ and vacAs1m1+ positive (99% and 90.4%, respectively). Unexpectedly, high resistance was noted for levofloxacin (20.9%) and amoxicillin (10.7%), while metronidazole (67.9%) and clarithromycin (11.2%) were similar to data from Latin America. Significant associations with age, gender, or histology were not noted, with the exception of levofloxacin (28%, P = 0.01) in those with histology limited to non-atrophic gastritis. Total antimicrobial usage in western Honduras of amoxicillin (17.3 DID) and the quinolones had the highest relative utilizations compared with other representative nations.

CONCLUSIONS

We observed significant H. pylori resistance to amoxicillin and levofloxacin in the context of high community antimicrobial utilization. This has implications in Central America for H. pylori treatment guidelines as well as antimicrobial stewardship programs.

Geospatial analyses identify regional hot spots of diffuse gastric cancer in rural Central America

Background

Geospatial technology has facilitated the discovery of disease distributions and etiology and helped target prevention programs. Globally, gastric cancer is the leading infection-associated cancer, and third leading cause of cancer mortality worldwide, with marked geographic variation. Central and South America have a significant burden, particularly in the mountainous regions. In the context of an ongoing population-based case-control study in Central America, our aim was to examine the spatial epidemiology of gastric cancer subtypes and H. pylori virulence factors.

Methods

Patients diagnosed with gastric cancer from 2002 to 2013 in western Honduras were identified in the prospective gastric cancer registry at the principal district hospital. Diagnosis was based on endoscopy and confirmatory histopathology. Geospatial methods were applied using the ArcGIS v10.3.1 and SaTScan v9.4.2 platforms to examine regional distributions of the gastric cancer histologic subtypes (Lauren classification), and the H. pylori CagA virulence factor. Getis-Ord-Gi hot spot and Discrete Poisson SaTScan statistics, respectively, were used to explore spatial clustering at the village level (30–50 rural households), with standardization by each village’s population. H. pylori and CagA serologic status was determined using the novel H. pylori multiplex assay (DKFZ, Germany).

Results

Three hundred seventy-eight incident cases met the inclusion criteria (mean age 63.7, male 66.3%). Areas of higher gastric cancer incidence were identified. Significant spatial clustering of diffuse histology adenocarcinoma was revealed both by the Getis-Ord-GI* hot spot analysis (P-value < 0.0015; range 0.00003–0.0014; 99%CI), and by the SaTScan statistic (P-value < 0.006; range 0.0026–0.0054). The intestinal subtype was randomly distributed. H. pylori CagA had significant spatial clustering only in association with the diffuse histology cancer hot spot (Getis-Ord-Gi* P value ≤0.001; range 0.0001–0.0010; SaTScan statistic P value 0.0085). In the diffuse gastric cancer hot spot, the lowest age quartile range was 21–46 years, significantly lower than the intestinal cancers (P = 0.024).

Conclusions

Geospatial methods have identified a significant cluster of incident diffuse type adenocarcinoma cases in rural Central America, suggest of a germline genetic association. Further genomic and geospatial analyses to identify potential spatial patterns of genetic, bacterial, and environmental risk factors may be informative.

Duodenal Ulceration following Holmium Laser Lithotripsy

The epidemiology of peptic ulcer disease (PUD) has changed considerably in the last several decades. Previously a chronic disease characterized by frequent recurrences with a high rate of surgical interventions, it is now largely a self-limited disease that is medically managed. The role of acid suppression was widely recognized as being important in the pathogenesis of PUD in the 19th century, while it was not until the 1980s and 1990s that the importance of Helicobacter pylori infection was identified. Today, PUD is largely caused by either H. pylori infection or nonsteroidal anti-inflammatory drug use. However, other less common etiologies of this disease are becoming more relevant as the prevalence of H. pylori decreases and proton pump inhibitor therapy is increasingly common. Here, we report a case of duodenal ulceration following bilateral rigid ureteroscopy with holmium laser lithotripsy.

Management patterns of gastric polyps in the United States

OBJECTIVE

Recent guidelines on endoscopic sampling recommend complete gastric polyp removal for solitary fundic polyps >10 mm, hyperplastic polyps >5 mm and all adenomatous polyps. We aim to describe endoscopic approach to polyps in the time period prior to the American Society of Gastrointestinal Endoscopy (ASGE) guidelines and to identify opportunities for clinical practice improvements.

DESIGN

Retrospective review of the Clinical Outcome Research Initiative (CORI) database, including all oesophagogastroduodenoscopies (OGDs). Reviewers grouped interventions during procedures based on instruments used for polyp sampling by forceps or snare polypectomy. Logistic regression estimated the effect of variables of interest on method of polypectomy.

RESULTS

Of 783 037 OGDs reported in the CORI database, 25 670 (3.3%) described gastric polyps and met the inclusion criteria. Mean gastric polyp size was 6.5±4.9 mm, and 46.2% and 14.5% were located in the corpus and antrum, respectively. Polyps in the forceps group were smaller than polyps in the snare group (5.7±4.0 mm vs 9.3±6.4 mm, respectively, p<0.001). We identified 1056 polyps (41.3%) >10 mm that only underwent forceps biopsy. Forceps were used more frequently in the gastric fundus.

CONCLUSIONS

Snare polypectomy was underused in gastric polyps, per current ASGE guidelines. Anatomical location and endoscopic features of polyps were important predictors of the approach to gastric polypectomy.

Tipping the Scale Toward Gastric Disease: A Host-Pathogen Genomic Mismatch?

PURPOSE OF REVIEW

Chronic infection with Helicobacter pylori infection is necessary but not sufficient to initiate development of intestinal-type gastric adenocarcinoma. It is not clear what additional factors tip the scale from commensal bacteria towards a pathogen that facilitates development of gastric cancer. Genetic variants in both the pathogen and host have been implicated, but neither alone explains a substantial portion of disease risk.

RECENT FINDINGS

In this review, we consider studies that address the important role of human and bacterial genetics, ancestry and their interactions in determining gastric disease risk. We observe gaps in the current literature that should guide future work to confirm the hypothesis of the interacting roles of host and bacterial genetics that will be necessary to translate these findings into clinically relevant information.

SUMMARY

We summarize genetic risk factors for gastric disease in both H. pylori and human hosts. However, genetic variation of one or the other organism in isolation insufficiently explains gastric disease risk. The most promising models of gastric disease risk simultaneously consider the genetic variation of both the H. pylori and human host, under a co-evolution model.

Perspectives on Strengthening Cancer Research and Control in Latin America Through Partnerships and Diplomacy: Experience of the National Cancer Institute's Center for Global Health

According to the Pan American Health Organization, noncommunicable diseases, including cancer, are the leading causes of preventable and premature death in the Americas. Governments and health care systems in Latin America face numerous challenges as a result of increasing morbidity and mortality from cancer. Multiple international organizations have recognized the need for collaborative action on and technical support for cancer research and control in Latin America. The Center for Global Health at the US National Cancer Institute (NCI-CGH) is one entity among many that are working in the region and has sought to develop a strategy for working in Latin America that draws on and expands the collaborative potential of engaged, skilled, and diverse partners. NCI-CGH has worked toward developing and implementing initiatives in collaboration with global partners that share the common objectives of building a global cancer research community and translating research results into evidence-informed policy and practice. Both objectives are complementary and synergistic and are additionally supported by an overarching strategic framework that is focused on partnerships and science diplomacy. This work highlights the overall strategy for NCI-CGH engagement in Latin America through partnerships and diplomacy, and highlights selected collaborative efforts that are aimed at improving cancer outcomes in the region.

Advancing Reliable Data for Cancer Control in the Central America Four Region

The Central America Four (CA-4) region, comprising Guatemala, Honduras, El Salvador, and Nicaragua, is the largest low- and middle-income country region in the Western Hemisphere, with over 36 million inhabitants. The CA-4 nations share a common geography, history, language, and development indices, and unified with open borders in 2006. The growing CA-4 cancer burden among the noncommunicable diseases is expected to increase 73% by 2030, which argues for a regional approach to cancer control. This has driven efforts to establish population-based cancer registries as a central component of the cancer control plans. The involvement of international and academic partners in an array of initiatives to improve cancer information and control in the CA-4 has accelerated over the past several years. Existing data underscore that the infectious cancers (cervical, stomach, and liver) are a particular burden. All four countries have committed to establishing regional population-based cancer registries and have advanced significantly in pediatric cancer registration. The challenges common to each nation include the lack of national cancer control plans and departments, competing health priorities, lack of trained personnel, and sustainability strategies. General recommendations to address these challenges are outlined. The ongoing regional, international, and academic cooperation has proven helpful and is expected to continue to be a powerful instrument to contribute to the design and implementation of long-term national cancer control plans.

Dynamics of Helicobacter pylori infection as a determinant of progression of gastric precancerous lesions: 16-year follow-up of an eradication trial

OBJECTIVE

To evaluate the long-term effect of cumulative time exposed to Helicobacter pylori infection on the progression of gastric lesions.

DESIGN

795 adults with precancerous gastric lesions were randomised to receive anti-H. pylori treatment at baseline. Gastric biopsies were obtained at baseline and at 3, 6, 12 and 16 years. A total of 456 individuals attended the 16-year visit. Cumulative time of H. pylori exposure was calculated as the number of years infected during follow-up. Multivariable logistic regression models were used to estimate the risk of progression to a more advanced diagnosis (versus no change/regression) as well as gastric cancer risk by intestinal metaplasia (IM) subtype. For a more detailed analysis of progression, we also used a histopathology score assessing both severity and extension of the gastric lesions (range 1-6). The score difference between baseline and 16 years was modelled by generalised linear models.

RESULTS

Individuals who were continuously infected with H. pylori for 16 years had a higher probability of progression to a more advanced diagnosis than those who cleared the infection and remained negative after baseline (p=0.001). Incomplete-type IM was associated with higher risk of progression to cancer than complete-type (OR, 11.3; 95% CI 1.4 to 91.4). The average histopathology score increased by 0.20 units/year (95% CI 0.12 to 0.28) among individuals continuously infected with H. pylori. The effect of cumulative time of infection on progression in the histopathology score was significantly higher for individuals with atrophy (without IM) than for individuals with IM (p<0.001).

CONCLUSIONS

Long-term exposure to H. pylori infection was associated with progression of precancerous lesions. Individuals infected with H. pylori with these lesions may benefit from eradication, particularly those with atrophic gastritis without IM. Incomplete-type IM may be a useful marker for the identification of individuals at higher risk for cancer.

Exposure to biomass smoke as a risk factor for oesophageal and gastric cancer in low-income populations: A systematic review

Background

Upper gastrointestinal cancers contribute significantly to cancer-related morbidity and mortality in sub-Saharan Africa, but they continue to receive limited attention. The high incidence in young adults remains unexplained, and the risk factors have not been fully described.

Methods

A literature search was conducted using the electronic database PubMed. Beginning from January 1980 to February 2016, all articles evaluating biomass smoke exposure with oesophageal and gastric cancer were reviewed.

Results

Over 70% of the African population relies on biomass fuel, meaning most Africans are exposed to biomass smoke throughout their lives. Cigarette smoke is an established risk factor for upper gastrointestinal cancers, and some of its carcinogenic constituents are also present in biomass smoke. We found eight case-control studies reporting associations between exposure to biomass smoke and oesophageal cancer, and two linking biomass smoke to gastric cancer. All of these papers reported significant positive associations between exposure and cancer risk. Further research is needed in order to fully define the constituents of biomass smoke, which could each have varying specific and synergistic or independent contributions to the development of upper gastrointestinal cancers

Conclusions

Exposure to biomass smoke is an environmental factor influencing the development of upper gastrointestinal cancers, especially in low-resource settings.

Congenital Malformations of the Central Nervous System in Rural Western Honduras: A 6-Year Report on Trends

BACKGROUND

Central nervous system (CNS) malformations, including neural tube defects (NTDs), are the second most common type of birth defects worldwide and are major causes of childhood disability and mortality. We report the first analysis of birth prevalence in Western Honduras of CNS malformations including NTDs over 6 consecutive years.

METHODS

Data from all patients with congenital CNS malformations and total live births for the period 2010-2015 were obtained through institution and regional registries from all 3 public referral hospitals in Western Honduras, representing 67 municipalities. Cases were identified using the International Classification of Diseases, Tenth Revision CNS malformation codes. Birth prevalence was calculated as cases per 10,000 live births.

RESULTS

From 123,903 live births, 275 cases of CNS malformations were identified (54% females, 58% NTDs). Six-year birth prevalence of CNS malformations was 13.9-31.1. Spina bifida variants and anencephaly represented 80% and 19% of reported NTDs, respectively. Total 6-year prevalence of NTDs in Western Honduras was 7.0-17.4 over years studied. In 6 municipalities, average prevalence was >30 (maximum 49.0).

CONCLUSION

This is the first study reporting disease burden of CNS malformations in Western Honduras. The nationwide birth prevalence of NTDs in rural Honduras may have decreased since the implementation of prenatal health policies in 2005. However, we identified regions with unexpectedly elevated prevalence, indicating high regional prevalence that could be targeted for improved preventive efforts, ultimately decreasing the burden of these conditions.

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.

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.