Low Incidence Of Gastric Cancer Research Articles

Endoskopická submukózní disekce v populaci s nízkým výskytem karcinomu žaludku

Summary: Introduction: Gastric cancer is a serious disease with a decreasing incidence. In the treatment of its early stages, endoscopic methods, especially endoscopic submucosal dissection (ESD), are used signifi cantly. Methods: We present the results of 64 consecutive ESD gastric lesions. We performed ESD using a conventional technique with a circular incision followed by submucosal dissection with the DualKnife tool. In cases of carcinomas, we assessed the outcome of ESD according to the eCura scoring system. Results: We achieved en bloc resection in 88% and R0 resection in 72%. Signifi cant bleeding occurred in 8% and perforation in 3%; we managed all complications conservatively, where the lethal rate was zero. Of the 58 ESD neoplastic lesions, 42 (72%) were curative. We considered 6 (10%) patients for surgery after ESD, and it was performed in 2 (3%). Conclusion: In the conditions of a country with a low incidence of gastric cancer, we consider ESD to be a safe method with signifi cant curative potential. Key words: gastric cancer – endoscopic submucosal dissection – curative resection

Epidemiology, Risk Factors for Gastric Cancer and Surveillance of Premalignant Gastric Lesions: A Prospective Cohort Study of Central Saudi Arabia.

(1) Background: Saudi Arabia (SA) is a country with a low incidence of gastric cancer (GC). In this study, we sought to assess the epidemiology of GC, its clinicopathological profiles, and its association with risk factors as well as to identify premalignant gastric lesions (PGL) and examine neoplastic progression. (2) Methods: This five-year prospective study screened for GC and PGL in asymptomatic Saudi patients, aged 45-75 years (n = 35,640) and living in Al Kharj, Riyadh province in central SA. Those who were positive in a high-sensitivity guaiac fecal occult blood test (HSgFOBT+) and had negative results in colonoscopy offered to undergo upper GI endoscopy (n = 1242). Factors associated with GC were examined. (3) Results: The five-year participation rate was 87% (1080/1242). The incidence rate of GC was 26.9 new cases per 100,000 population per year (9.6 new cases per year/total population at risk-35,640), and it was 8.9 cases per 1000 persons per year among the 1080 subjects with HSgFOBT+ and negative colonoscopy results. The five-year mortality rate was 67% among patients with GC (n = 48), 3.0% among participants in the gastric screening program (n = 1080) and 0.09% among the original population participating in the colorectal screening program (n = 35,640). Intestinal-type adenocarcinoma was the most frequent type (77%), with the tumor most commonly located in the antrum (41%). Overall, 334 participants had PGL, and seven of them (2.1%) showed neoplastic progression to GC during the follow-up. Factors associated with GC were age, Helicobacter pylori (HP) infection, obesity (body mass index BMI > 30), smoking, a diet of salty preserved foods, low income and a family history of GC. (4) Conclusions: The incidence of GC is low in central SA, but screening for PGL and GC among patients with HSgFOBT+ and negative colonoscopy may prevent or result in the early treatment of GC. HP eradication, normal body weight, not smoking and adhering to a healthy diet can reduce the risk of GC. The resulting data provide important input for the improvement of national guidelines.

Menstrual and Reproductive Factors for Gastric Cancer in Postmenopausal Women: The 2007-2020 Korea National Health and Nutrition Examination Survey.

Globally, the incidence of gastric cancer is lower in women than in men. It is thought that menstrual and reproductive factors may be related to their lower incidence of gastric cancer. This cross-sectional study examined menstrual, reproductive, and other factors in 20,784 postmenopausal women from the 2007-2020 Korea National Health and Nutrition Examination Survey (KNHANES). A univariate logistic regression analysis was performed, and then a multivariate logistic regression analysis for significant factors in the univariate analysis was conducted. In the multivariate logistic regression analysis, the age at menarche (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.00-1.06, p = 0.035) and myocardial infarction (OR 2.43, 95% CI 1.05-5.62, p = 0.026) showed a significant association with increased incidence of gastric cancer. The age at menopause (OR 0.97, 95% CI 0.95-1.00, p = 0.03), the age at the first childbirth (OR 0.93, CI 0.89-0.97, p = 0.007), and the experience of alcohol consumption (OR 0.68, 95% CI 0.5-0.91, p = 0.003) showed a significant association with a decreased incidence of gastric cancer. Late menarche, early menopause, early aged first childbirth, and myocardial infarction are estimated to be risk factors for gastric cancer in postmenopausal Korean women.

Differences in outcomes between premenopausal women and men with gastric cancer in the United States.

e16066 Background: Over the past decades, the incidence rate of gastric cancer has only dropped by 1.5% despite the identification of modifiable risk factors. Gastric cancer has a male predominance; the lower incidence in females may be associated with a protective hormonal effect. Studies reported the expression of estrogen receptor alpha (ERα) and beta (ERβ) in gastric cancer, yet their roles in incidence and prognosis remain inconclusive. We analyzed the hormonal association with the in-hospital outcomes using a cohort of premenopausal women and men with gastric cancer. Methods: Using Nationwide Inpatient Sample Database from 2016 to 2019, we selected adult women under age 51 as premenopausal as defined by the American College of Obstetricians and Gynecologists and compared to men of the same age group. The primary outcome was in-hospital mortality. Secondary outcomes included hospital length of stay (LOS), thromboembolism, and gastrointestinal hemorrhage. Types of surgical interventions were also studied. Data were extracted using ICD-10 codes. Results: A total of 25,595 patients (based on a weighted sample) were included in the analysis; 44.6% were men, 7.5% were obese, and 13.7% were smokers. White race was most common (32.9% men vs 41.9% women), followed by Hispanic (34% vs 27.1%), African American (16.3% vs 16.1%), Asian (8.8% vs 7.7%), and Native American (1.3% vs 0.8%); p < 0.05. The prevalence of common comorbidities was consistent among men and women; 29.5% had hypertension, 10.4% had diabetes mellitus, 2% had coronary artery disease, and 2.8% had congestive heart failure (CHF). Men had higher in-hospital mortality (7.9% vs 6%; p < 0.05) and incidence of gastrointestinal hemorrhage compared to women (16.2% vs 9.7%; p < 0.05). The median LOS was 5 days (IQR: 3-9) in men and 5 days (IQR: 2-9) in women; p = 0.59. The incidence of venous thromboembolism was 8.2% (no difference among sex) and myocardial infarction was 0.6% (0.8% men vs 0.2% women; p < 0.05). Notably, in this younger population (age: 18-51), 63% patients had metastatic disease (62.8% men vs 63.4% women; p = 0.92). Among all patients, 27.8% underwent gastrectomy: partial gastrectomy (21.2%), total gastrectomy (4.9%), and robotic gastrectomy (1.7%). The multivariate logistic regression model adjusted for baseline demographics, comorbidities, metastatic disease, and socioeconomic status indicated that male sex (OR: 1.37; 95% CI: 1.07-1.73; p < 0.05), Asian race (OR: 1.64; 95% CI: 1.09-2.46; p < 0.05), CHF (OR: 4.05; 95% CI: 2.44-6.74; p < 0.05), and metastasis (OR: 3.84; 95% CI: 2.73-5.37; p < 0.05) were independent risk factors of in-hospital mortality. Conclusions: Our study shows that women have a lower incidence of gastric cancer and associated in-hospital mortality, which may support the protective role of estrogen. This highlights the need for translational and clinical studies on potential actionable mechanisms in gastric cancer management.

Effect of Helicobacter pylori Eradication on Gastric Cancer Prevention: Updated Report From a Randomized Controlled Trial With 26.5 Years of Follow-up

Helicobacter pylori infection is considered as the most important risk factor in the pathogenesis of gastric cancer. This study aims to evaluate the long-term effects of H pylori eradication treatment on the incidence and mortality of gastric cancer among a high-risk population. This prospective, randomized, placebo-controlled trial was conducted in a high-risk area in southern China in July 1994. A total of 1630 asymptomatic, H pylori-infected individuals were randomly assigned to receive standard triple therapy for H pylori eradication (n= 817) or placebo (n= 813), and were followed up until December 2020. The primary outcome was incidence of gastric cancer. Total and cause-specific mortalities were the secondary outcomes. During 26.5 years of follow-up, 21 participants (2.57%) in the treatment arm and 35 (4.31%) in the placebo arm were diagnosed with gastric cancer. Participants receiving H pylori treatment had a lower incidence of gastric cancer compared with their placebo counterparts (hazard ratio [HR], 0.57; 95% CI, 0.33-0.98). More obvious risk reduction was observed among those without premalignant gastric lesions (HR, 0.37; 95% CI, 0.15-0.95) and those without dyspepsia symptoms at baseline (HR, 0.44; 95% CI, 0.21-0.94). Furthermore, compared with 32 cases of gastric cancer observed among 527 participants with persistent H pylori infection in the placebo group, only 16 were identified in 625 subjects with successful eradication in the treatment group (HR, 0.46; 95% CI, 0.26-0.83). However, there were no statistically significant differences for any mortality end points between the 2 groups. Eradication of H pylori might confer a long-term protection against gastric cancer in high-risk populations, especially for infected individuals without precancerous gastric lesions at baseline.

Changing trends in gastric cancer incidence and mortality: the role of upper endoscopy in low-risk countries.

Gastric cancer, which is diagnosed in approximately one million new patients annually, is a significant contributor to global cancer burden and cancer-related mortality [1]. East Asia, eastern Europe, and Latin America have the highest incidences, while North America and most of western Europe have relatively low incidences [2]. This geographical variation is thought to be associated with several different predisposing and etiologic factors among the countries, such as tumor biology, Helicobacter pylori (H. pylori) infection rate, cigarette smoking, and a high sodium diet with salt-preserved foods. Global age-standardized gastric cancer incidence has steadily declined over the past century, particularly in high-risk countries such as Korea and Japan. This trend has been linked to a decline in noncardia cancer because of the eradication of H. pylori [2]. Contrarily, in countries with low gastric cancer incidence, such as those in western Europe and the USA, the decline in gastric cancer has reduced, especially in the middle-aged population [1] [2]. This phenomenon may also be related to changes in H. pylori infection patterns or the increased proportion of cardia cancer related to epidemic obesity and gastroesophageal reflux disease [1]. As with incidence, global gastric cancer mortality has also decreased [2]. Improvements in surgical techniques and the development of chemotherapy regimens have led to better survival outcomes. Above all, early detection of cancer is a crucial factor contributing to the decline in mortality.

Toll-Like Receptor 1 Locus Re-examined in a Genome-Wide Association Study Update on Anti–Helicobacter pylori IgG Titers

A genome-wide significant association between anti-Helicobacter pylori (H pylori) IgG titers and Toll-like receptor (TLR1/6/10) locus on 4p14 was demonstrated for individuals of European ancestry, but not uniformly replicated. We re-investigated this association in an updated genome-wide association study (GWAS) meta-analysis for populations with low gastric cancer incidence, address potential causes of cohort heterogeneity, and explore functional implications of genetic variation at the TLR1/6/10 locus. The dichotomous GWAS (25% individuals exhibiting highest anti-H pylori IgG titers vs remaining 75%) included discovery and replication sampls of, respectively, n= 15,685 and n= 9676, all of European ancestry. Longitudinal analysis of serologic data was performed on H pylori-eradicated subjects (n= 132) and patients under surveillance for premalignant gastric lesions (n= 107). TLR1/6/10 surface expression, TLR1 mRNA, and cytokine levels were measured in leukocyte subsets of healthy subjects (n= 26) genotyped for TLR1/6/10 variants. The association of the TLR1/6/10 locus with anti-H pylori IgG titers (rs12233670; β=-0.267 ± SE 0.034; P= 4.42× 10-15) presented with high heterogeneity and failed replication. Anti-H pylori IgG titers declined within 2-4 years after eradication treatment (P= 0.004), and decreased over time in patients with premalignant gastric lesions (P < 0.001). Variation at the TLR1/6/10 locus affected TLR1-mediated cytokine production and TLR1 surface expression on monocytes (P= 0.016) and neutrophils (P= 0.030), but not mRNA levels. The association between anti-H pylori IgG titers and TLR1/6/10 locus was not replicated across cohorts, possibly owing to dependency of anti-H pylori IgG titers on therapy, clearance, and antibody decay. H pylori-mediated immune cell activation is partly mediated via TLR1 signaling, which in turn is affected by genetic variation.

Implementation of endoscopic submucosal dissection in a country with a low incidence of gastric cancer: Results from a prospective national registry

Implementation of endoscopic submucosal dissection in a country with a low incidence of gastric cancer: Results from a prospective national registry

Helicobacter pylori virulence factors and host genetic polymorphisms in a low gastric cancer incidence and high H pylori prevalence country

<i>Helicobacter pylori</i> virulence factors and host genetic polymorphisms in a low gastric cancer incidence and high <i>H pylori</i> prevalence country

Implementation of endoscopic submucosal dissection in a country with a low incidence of gastric cancer: Results from a prospective national registry.

IntroductionEndoscopic submucosal dissection (ESD) has become the treatment of choice for early gastric malignancies. In recent years, the ESD technique has been implemented in Western countries with increasing use.ObjectivesTo describe the results of gastric ESD in a Western country with a low incidence of gastric cancer.Patients and MethodsThe prospective national registry was conducted over 4 years in 23 hospitals, including 30 endoscopists. Epithelial and subepithelial lesions (SEL) qualified to complete removal with ESD were assessed. The technique, instruments, and solution for submucosal injection varied at the endoscopist's discretion. ESD was defined as difficult when: en‐bloc resection was not achieved, had to be converted to a hybrid resection, lasted more than 2 h or an intraprocedural perforation occurred. Additionally, independent risk factors for difficult ESD were analyzed.ResultsTwo hundred and thirty gastric ESD in 225 patients were performed from January 2016 to December 2019 (196 epithelial and 34 SEL). Most lesions were located in the lower stomach (111; 48.3%). One hundred and twenty‐eight (55.6%) ESD were considered difficult. The median procedure time was 105 min (interquartile range [IQR]: 60–150). The procedure time for SEL was shorter than for epithelial lesions (90 min [45–121] vs. 110 min [62–160]; p = 0.038). En‐bloc, R0, and curative resection rates were 91.3%, 75.2%, and 70.9%, respectively. Difficult ESD had lower R0 resection rates than ESD that did not meet the difficulty criteria (64.8% and 87.6%; p = 0.000, respectively). Fibrosis and poor maneuverability were independent factors associated with difficult ESD (OR 3.6, 95%CI 1.1–11.74 and OR 5.07, 95%CI 1.6–16.08; respectively).ConclusionsAlthough the number of cases is limited, the results of this analysis show acceptable en‐bloc and R0 rates in gastric ESD considering the wide variability in experience among the operators. Fibrosis and poor maneuverability were associated with more difficulty in completing ESD.

High Salt Intake in Helicobacter Pylori Infected Individuals Can Significantly Increase the Risk of Gastric Cancer; a Global Analysis

The odds ratio with 95CIs was used to evaluated the synergistic effects between high salt intake and H. pylori infection among gastric cancer cases. Heterogeneity was assessed by I2 index and Cochrane Q-test; In addition, the presence of publication bias was measured using Beggâ��s p-value and Eggerâ��s p-value test (18). There were 7 studies met our criteria. These studies were conducted during 2003-2019 in Korea, Japan, United states, China, and Portugal. We evaluated data of 8,068 cases. H. pylori infection was confirmed by ELISA and UBT in these eligible studies (Table 1). The frequency of gastric cancer in habitual high salt intakes with positive H. pylori infection was significantly greater than those preference salty food with negative H. pylori infection (Chi-square: 5.33; p-value: 0.02). Our results suggested that there is a positive association between high salt intake and risk of gastric cancer in H. pylori infected-individuals (OR: 1.47; 95CI: 1.01-2.15; p-value: 0.04; I2: 83.6; Q-value: 36.6; Beggâ��s p-value: 0.13; Eggerâ��s p-value: 0.25) (Fig. 1). Gastric cancer is one of the top cause of cancer-related death in the world (1). Unfortunately, gastric cancer has a poor-prognosis and untreated early gastric cancer lesions will progress to advanced gastric cancer during 4-5 years (2). Gastric cancer is a heterogeneous malignancy with multifactorial causes including socio-economic status, diet, environmental condition, genetic polymorphism as well as infectious agents particularly chronic infection by Helicobacter pylori (3). In 1994, the International Agency for Research on Cancer (IARC) announced that H. pylori is considered as class I carcinogens and etiologic cause of human gastric cancer (4). However, a high rate of H. pylori infection in areas with a low incidence of gastric cancer remains an enigma (5). It has been suggested that H. pylori infection alone cannot cause gastric cancer without synergistic effects of lifestyle, diet, etc (6-7). On the other hand, there is evidence that dietary salt has an association with gastric adenocarcinoma (8-9). Therefore, it may that H. pylori infection and high salt intakes have synergistic effects in the development of gastric cancer. the previous studies reveal that salt cause upregulation of H. pylori cagA gene during in vitro experiments (10). We performed a comprehensive literature search in several databases including PubMed, Scopus, Embase, and Google scholar using search terms consisting â��Helicobacter pyloriâ��, â��Saltâ��, â��Gastric cancerâ��, â��Dietaryâ�� and â��Salt intakeâ�� without limitation in time and language. The potential relevant documents were evaluated and the required data such as first author, publication year, country, total cases, the frequency of high salt intake among H. pylori-infected cases with gastric cancer or odds ratio corresponding 95 confidence intervals (95CIs), and H. pylori diagnostic test were summarized in Table 1. The odds ratio with 95CIs was used to evaluate the synergistic effects between high salt intake and H. pylori infection among gastric cancer cases. Heterogeneity was assessed by I2 index and Cochrane Q-test; In addition, the presence of publication bias was measured using Beggâ��s p-value and Eggerâ��s p-value test (18).  There were 7 case-control studies that met our criteria. These studies were conducted during 2003-2019 in Korea, Japan, United states, China, and Portugal. We evaluated data of 8,068 cases. H. pylori infection was confirmed by ELISA and UBT in these eligible studies (Table 1). The sodium concentration was assessed by history, urinary sodium, as well as Food frequency questionnaires (FFQs) in these studies.The frequency of gastric cancer in habitual high salt intakes with positive H. pylori infection was significantly greater than those who preference salty food with negative H. pylori infection (Chi-square: 5.33; p-value: 0.02). Our results suggested that there is a positive association between high salt intake and risk of gastric cancer in H. pylori infected-individuals (OR: 1.47; 95CI: 1.01-2.15; p-value: 0.04; I2: 83.6; Q-value: 36.6; Beggâ��s p-value: 0.13; Eggerâ��s p-value: 0.25) (Fig 1). Tsugane et al, 2004 were suggested that there is a significant relation between salt intake and the subsequent risk of gastric cancer in a Japanese population (19). In addition, Ge et al., 2012 provided a systematic review to show the association between Habitual dietary salt intake and risk of developing to gastric cancer using 11 retrospective single-center studies (20). Â

Long-Term Follow-up of Gastric Precancerous Lesions in a Low GC Incidence Area.

INTRODUCTION:Data on the evolution of gastric precancerous lesions (GPL), especially in countries of a Low gastric cancer incidence area are limited. Our objective was to study a long-term evolution of GPL in France.METHODS:All the patients diagnosed with GPL (atrophic gastritis, intestinal metaplasia [IM], and dysplasia) between 2000 and 2015 and fulfilling criteria for evolution assessment (at least 2 endoscopies, minimal follow-up of 6 months, and at least 2 biopsies obtained from the antrum and corpus) were included. Clinical and endoscopic data were analyzed, and histological samples were reviewed by an expert pathologist with evaluation of the Operative Link on Gastric Intestinal Metaplasia Assessment stage and type of IM.RESULTS:From the 507 patients with GPL, 79 fulfilled the strict criteria. During a mean follow-up of 66 months, during which the patients had a mean number of 4 endoscopies (min–max: 2–21) with 9 biopsies/endoscopy, a stability was observed in 70% of patients. Progression occurred in 14% of patients, within a mean delay of 62.1 months (min–max: 17–99). Progression of the lesions was significantly higher in patients with incomplete type of IM (relative risk of progression for incomplete IM: 11.5; 95% confidence interval 2.5–53.1). Regression of IM occurred in 16% of the patients, after a mean delay of 90 months.DISCUSSION:This study shows that the patients with antrum-limited IM, especially of incomplete type, are at the highest risk of developing gastric cancer. In most patients, however, the lesions remain stable, which highlights the need for additional markers to better target the patients at risk of progression.

Risk of Progression of Gastric Intestinal Metaplasia Is Significantly Greater When Detected in Both Antrum and Body

Gastric cancer (GC) is the fifth leading cause of cancer-related death worldwide. GC is usually preceded by a cascade of well-defined precursor lesions, set in place by an environmental trigger (H. pylori) including intestinal metaplasia (GIM) and dysplasia. To investigate the rates of progression of GIM to dysplasia and GC in a region of low gastric cancer incidence. We identified all patients diagnosed with GIM between January 1, 2008, and June 30, 2012. Any repeat upper endoscopy more than 1year after index diagnosis and before December 31, 2018, was considered follow-up. Carcinomas the bulk of which were macroscopically located below the OGJ were considered primary gastric cancer. Progression to more advanced lesions was observed in six patients (0.6%). Four patients (three male) developed GC at median age 74years (SD 6). Two patients progressed to dysplasia (one male) at median age 71years (SD 4). Patients with GIM in both gastric antrum and body were significantly more likely to progress than those with GIM in only one location (3.1% vs. 0.4%) (p value 0.017). Fifty-eight patients who had H. pylori eradicated were followed up. No progression to dysplasia or GC was noted in this group, with 28 patients having persistent GIM at follow-up. Patients with GIM in both antrum and body had a significantly increased risk of progression and warrant close attention. This is comparable to routinely followed premalignant conditions such as Barrett's esophagus and Colonic Polyps, and appropriate surveillance protocols should be followed in this group.

S3442 A Trip Through the Pylorus - A Rare Case of a Gastric Adenocarcinoma Invading the Duodenum and Literature Reivew

INTRODUCTION: We present a rare case in a 61-year-old African American who shows one such case an interesting case of multiple gastric adenocarcinoma involving the gastric antrum and pylorus that extended into the duodenum. CASE DESCRIPTION/METHODS: A 61-year-old male without medical history presented with abdominal pain of one month acutely worsening over the 2 weeks. The pain was diffuse in nature, 9/10 in severity, with decreased appetite and 25lbs weight loss without exacerbating or relieving factors. Physical exam showed for RUQ and LUQ tenderness. Hepatomegaly was present with a firm mass palpated below the epigastrium. Labs were unremarkable. CT of abdomen and pelvis with contrast revealed hypoattenuating lesions in liver and spleen. An enlarged, heterogeneous pancreatic head with dilated duct and multiple enlarged lymph nodes, including a necrotic lymph node were found with the latter causing mass effect of structure. The stomach had a suspicious gastric mass with irregular wall thickening along the greater curvature and mesenteric stranding. There were multiple omental masses, peritoneal masses in RUQ and LUQ with significant retroperitoneal and pelvic lymphadenopathy. Subsequent upper endoscopy showed an abnormal nodular mucosal area in the junction of gastric body and antrum with a large gastric polyp in the adjacent area that was biopsied. Initially the top differential was lymphoma on accord that it does not respect the gastric-duodenal junction however, the pathology report of the abnormal gastric tissue revealed a poorly differentiated gastric adenocarcinoma that also involved duodenal mucosa with loss of nuclear expression of PMS-2 and MLH-1. Helicobacter Pylori testing was also noted be positive. Patient was started on FOLFOX therapy without benefit. Treatment was switched to Pembrolizumab therapy as tumor was MMR deficient with good response. DISCUSSION: The incidence of duodenal invasion in lower stomach cancer ranges from 13.5 to 33.2% mainly based on populations of Asian heritage, where the prevalence of gastric cancers is much higher than the rest of the world. Our patient is an African American male, and at the time of writing this case report our search showed that there are a handful of published cases of gastric cancer invading the duodenum in which highlights this rarity. We hypothesize that the reduced presentation of similar presentations may be low due to overall low incidence of gastric cancer in the United States, which has rapidly declined over the past 50 years.Figure 1.: Gastric antrum polyp.Figure 2.: Pre-pyloric tissue extending through pylorus into duodenal bulb.Figure 3.: Duodenal Bulb – Abnormal mucosa.

Regional variations in Helicobacter pylori infection, gastric atrophy and gastric cancer risk: The ENIGMA study in Chile.

Regional variations in gastric cancer incidence are not explained by prevalence of Helicobacter pylori, the main cause of the disease, with several areas presenting high H. pylori prevalence but low gastric cancer incidence. The IARC worldwide H. pylori prevalence surveys (ENIGMA) aim at systematically describing age and sex-specific prevalence of H. pylori infection around the world and generating hypotheses to explain regional variations in gastric cancer risk. We selected age- and sex-stratified population samples in two areas with different gastric cancer incidence and mortality in Chile: Antofagasta (lower rate) and Valdivia (higher rate). Participants were 1-69 years old and provided interviews and blood for anti-H. pylori antibodies (IgG, VacA, CagA, others) and atrophy biomarkers (pepsinogens). H. pylori seroprevalence (Age-standardized to world population) and antibodies against CagA and VacA were similar in both sites. H. pylori seroprevalence was 20% among children <10 years old, 40% among 10-19 year olds, 60% in the 20-29 year olds and close to or above 80% in those 30+ years. The comparison of the prevalence of known and potential H. pylori cofactors in gastric carcinogenesis between the high and the low risk area showed that consumption of chili products was significantly higher in Valdivia and daily non-green vegetable consumption was more common in Antofagasta. Pepsinogen levels suggestive of gastric atrophy were significantly more common and occurred at earlier ages in Valdivia, the higher risk area. In a multivariate model combining both study sites, age, chili consumption and CagA were the main risk factors for gastric atrophy. The prevalence of H. pylori infection and its virulence factors was similar in the high and the low risk area, but atrophy was more common and occurred at younger ages in the higher risk area. Dietary factors could partly explain higher rates of atrophy and gastric cancer in Valdivia. The ENIGMA study in Chile contributes to better understanding regional variations in gastric cancer incidence and provides essential information for public health interventions.

P-116 Impact of the number of harvested lymph nodes on survival in Egyptian patients with gastric cancer: Middle Eastern tertiary center experience

Radical gastrectomy with regional lymphadenectomy is the standard of care for all resectable gastric cancers. LN dissection has been debated over the years by different oncologic surgeons. In Japan, D2 lymphadenectomy was considered the standard procedure, whereas, in Asian countries, extended lymphadenectomy achieved superior survival and reduced recurrence rates. On the contrary, in Western countries, D2 lymphadenectomy was not considered a standard of care in clinical practice, possibly due to lower incidence of gastric cancer and lesser confidence of western oncologic surgeons in this procedure as a result of higher rates of surgical complications and perioperative mortality.

Genetic variation in the cag pathogenicity island of Helicobacter pylori strains detected from gastroduodenal patients in Thailand.

There is a lack of evidence of genetic variation in the Helicobacter pylori cag-PAI in Thailand, a region with the low incidence of gastric cancer. To clarify this issue, variation in the H. pylori cag-PAI in strains detected in Thailand was characterized and simultaneously compared with strains isolated from a high-risk population in Korea. The presence of ten gene clusters within cag-PAI (cagA, cagE, cagG, cagH, cagL, cagM, cagT, orf13, virB11, and orf10) and IS605 was characterized in H. pylori strains detected from these two countries. The cagA genotypes and EPIYA motifs were analyzed by DNA sequencing. The overall proportion of the ten cag-PAI genes that were detected ranged between 66 and 79%; additionally, approximately 48% of the strains from Thai patients contained an intact cag-PAI structure, while a significantly higher proportion (80%) of the strains from Korean patients had an intact cag-PAI. A significantly higher proportion of IS605 was detected in strains from Thai patients (55%). Analysis of cagA genotypes and EPIYA motifs revealed a higher frequency of Western-type cagA in Thai patients (87%) relative to Korean patients (8%) who were predominately associated with the East Asian-type cagA (92%). Variations in the Western-type cagA in the Thai population, such as EPIYA-BC patterns and EPIYA-like sequences (EPIYT), were mainly detected as compared with the Korean population (p < 0.05). In summary, H. pylori strains that colonize the Thai population tend to be associated with low virulence due to distinctive cag-PAI variation, which may partially explain the Asian paradox phenomenon in Thailand.

1233 Disaggregation of Gastric Cancer Risk Between Asian American Subgroups

INTRODUCTION: Within the United States (US), 26,000 new cases of gastric cancer (GC) and over 10,000 related deaths occur annually. Within the US, Asians and Pacific Islanders (API) in aggregate are known to be at increased risk for GC. There is limited data regarding GC risk between API subgroups. While screening of the general American population is not cost-effective, improved understanding of GC risk by disaggregated API subgroups may allow for targeted and cost-effective endoscopic screening. METHODS: All incident cases of GC diagnosed in the years 2011-2014 were identified from the Surveillance, Epidemiology, and End Results Program registries incorporating California (CA) and Hawaii (HI). From these incidence registries, API subgroup of patients were identified: Korean (CA and HI), Japanese (CA and HI), Chinese (CA and HI), Vietnamese (CA only), Filipino (CA and HI), and Indian (CA only). API subgroup population estimates were obtained from the American Community Survey (ACS). The age-adjusted incidence rates per 100,000 population and 95% confidence intervals (CIs) were generated for each subgroup, and among non-Hispanic whites (NHWs) for reference. RESULTS: 2,132 incident API GCs, and 3,984 incident NHW GCs were identified. Significant differences in GC incidence exist between API subgroups. In CA, Koreans (23.4 per 100,000, 95% CI 15.8 to 31.0) and Japanese (21.4, CI 16.1 to 26.7) demonstrated high incidence, Chinese (11.0, CI 10.4 to 11.6) and Vietnamese (10.3, CI 7.8 to 12.8) demonstrated intermediate incidence, and Filipinos (4.6, CI 3.4 to 5.8) and Indians (3.7, CI 2.9 to 4.5) demonstrated low incidence (Figure 1). The incidence among NHWs in CA was 6.6 (CI 6.0 to 7.2). In HI, Koreans (16.3, CI 11.4 to 21.2) and Japanese (16.0, CI 12.5 to 19.5) demonstrated high incidence, while Filipino (5.0, CI 3.4 to 6.6) and Chinese (4.8, CI 2.1 to 7.5) demonstrated low incidence (Figure 2). The incidence among NHWs in HI was 4.7 (CI 3.1 to 6.3). CONCLUSION: Substantial heterogeneity in risk for GC exist between API subgroups. Koreans and Japanese are at highest risk, with incidence nearly five-fold higher than Filipinos and Indians. This suggests that the higher GC-risk in APIs in aggregate are driven by certain subgroups. This may hold implications for screening for GC. There is a lower incidence of GC in HI compared to CA, even within API subgroups. These differences may represent cohort effects from generational migration, or regional dietary and environmental differences.

Infections with Helicobacter pylori and challenges encountered in Africa.

Helicobacter pylori (H. pylori) is the causative agent of gastritis, peptic ulcer disease, mucosa associated lymphoid tissue lymphoma and gastric cancer (GC). While this bacterium infects 50% of the world’s population, in Africa its prevalence reach as high as 80% as the infection is acquired during childhood. Risk factors for H. pylori acquisition have been reported to be mainly due to overcrowding, to have infected siblings or parent and to unsafe water sources. Despite this high H. pylori prevalence there still does not exist an African guideline, equivalent to the Maastricht V/Florence Consensus Report of the European Helicobacter and Microbiota Study Group for the management of this infection. In this continent, although there is a paucity of epidemiologic data, a contrast between the high prevalence of H. pylori infection and the low incidence of GC has been reported. This phenomenon is the so-called “African Enigma” and it has been hypothesized that it could be explained by environmental, dietary and genetic factors. A heterogeneity of data both on diagnosis and on therapy have been published. In this context, it is evident that in several African countries the increasing rate of bacterial resistance, mainly to metronidazole and clarithromycin, requires continental guidelines to recommend the appropriate management of H. pylori. The aim of this manuscript is to review current literature on H. pylori infection in Africa, in terms of prevalence, risk factors, impact on human health, treatment and challenges encountered so as to proffer possible solutions to reduce H. pylori transmission in this continent.

An Ecological Study on the Risk of Gastric Cancer With Helicobacter Pylori Prevalence and Other Potential Cofactors in Korea

Background: Korea has a high incidence of gastric cancer and a high prevalence of Helicobacter pylori infection. Observation of prevalence trends and determination of risk factors for gastric cancer are important to establish health policies to prevent and reduce the burden of disease. Currently, there is no evidence of complete correlation between prevalence of H. pylori infection and the occurrence of gastric cancer. Several explanations have been proposed for the paradox of high prevalence of infection and low gastric cancer incidence in certain places, including diet and salt consumption, genetic susceptibility, other infections, aflatoxin-contaminated food, and the interaction of all these factors, but none of them has been clearly established. Aim: To explore the potential effects of prevalence of H. pylori infection and other risk factors on gastric cancer incidence in Korea. Methods: Information on gastric cancer incidence, prevalence of H. pylori infection, and the risk factors for gastric cancer were evaluated from nationally representative data - the Korean National Cancer Registry, nationwide routine health check-up surveillance system, and National Health and Nutrition Survey, respectively. Secular trends of H. pylori infection prevalence and age-standardized incidence rates for gastric cancer by region were examined. Furthermore, trends of income level, education level, marital status, number of family members, smoking status, drinking status, obesity, diabetes, hypertension, dyslipidemia, and age-standardized incidence rates for gastric cancer by region were examined. Results: Gastric cancer incidence showed a decreasing trend from 2011 to 2015; 50.6%–44.4% for men and 22.1%–17.0% for women. The prevalence of H. pylori infection also showed a decreasing trend; from 66.9% in 1998%–54.4% in 2011. In Korea, areas with high prevalence of H. pylori infection also showed high gastric cancer incidence. However, the Chungcheong area showed relatively low prevalence of H. pylori infection, but had the highest gastric cancer incidence in Korea. Other factors which showed similar effects on gastric cancer incidence, like H. pylori infection were large family size (4 or more family members), low income, low education, and obesity. The effect of introduction of 'National Cancer Screening Program' will be evaluated in the final outcome. Conclusion: The results of this study indicated that significant regional differences exist between trends in H. pylori infection prevalence and gastric cancer incidence in Korea. Also, the possibility of lack of association between H. pylori prevalence and the incidence of gastric cancer are suggested. Overall, this study suggests the need for further research to explore potential factors accounting for regional differences in gastric cancer incidence in Korea.