Gastric Cancer in Northern Canadian Populations: A Focus on Cardia and Non-Cardia Subsites

Increasing our knowledge about the epidemiology of Helicobacter pylori in Nunavik's Inuit population (Québec, Canada) using Qanuilirpitaa? 2017 cross-sectional survey

Helicobacter pylori is a bacterium that may colonise and proliferate in human stomachs, leading invariably to chronic inflammation and, to a lesser extent, to peptic ulcers and cancer. The main objective of this study is to describe the epidemiology surrounding H. pylori in Nunavik's Inuit population using the 2004 and 2017 Health Surveys. Estimated prevalences were 70.9% for bacterial colonisation using a stool antigens test (SAT), 72.5% for anti-H. pylori antibodies, 12.7% for faecal occult blood in participants aged ≥ 50 and respectively of 28.4%, 11.2% and 2.4% for a prior diagnosis of colonisation, gastritis and peptic ulcer in the medical charts, with under five cases of gastric cancer reported. Variables associated with higher SAT+ prevalence were the number of household members (prevalence ratio [PR] = 1.03) and age (quadratic relationship), whereas mainly drinking municipal (PR = 0.84) and natural water (PR = 0.72) compared to bottled water, and increasing alcohol consumption (PR = 0.96) were associated with reduced prevalence. Despite current regional guidelines targeting high risk individuals in the context of high prevalence, Nunavik's health authorities must remain vigilant by following gastric cancer incidence and the rapid evolution of guidelines, while considering local realities.

Infectious diseases in Indigenous populations in North America: learning from the past to create a more equitable future

The COVID-19 pandemic, although a profound reminder of endured injustices by and the disparate impact of infectious diseases on Indigenous populations, has also served as an example of Indigenous strength and the ability to thrive anew. Many infectious diseases share common risk factors that are directly tied to the ongoing effects of colonisation. We provide historical context and case studies that illustrate both challenges and successes related to infectious disease mitigation in Indigenous populations in the USA and Canada. Infectious disease disparities, driven by persistent inequities in socioeconomic determinants of health, underscore the urgent need for action. We call on governments, public health leaders, industry representatives, and researchers to reject harmful research practices and to adopt a framework for achieving sustainable improvements in the health of Indigenous people that is both adequately resourced and grounded in respect for tribal sovereignty and Indigenous knowledge.

Changes in Gastric Pathology after H. pylori Treatment in Community-Driven Research Aimed at Gastric Cancer Prevention

Community-driven projects have characterized Helicobacter pylori (Hp) infection in Indigenous communities in the Northwest Territories (NT) and Yukon (YT), Canada. These projects address concerns about the frequent diagnosis of Hp infection among community members and its relation to gastric cancer deaths, perceived to occur with alarming frequency in this region. Projects included breath-test screening for Hp infection, gastroscopy with gastric biopsies, and treatment to eliminate Hp infection. Previous project results showed a high prevalence of stomach pathologies associated with increased cancer risk among Hp-positive participants at baseline. This analysis describes changes in precancerous gastric pathologies in project participants who had gastroscopy before baseline treatment during 2008-2013 and again in 2017. Throughout the study period, the same pathologist graded Hp density, active gastritis, chronic gastritis, atrophic gastritis, and intestinal metaplasia using the updated Sydney System. Of 310 participants from three communities with baseline pathology data, 69 had follow-up pathology data. Relative to baseline, the prevalence of Hp infection and precancerous gastric pathology was substantially lower at follow-up; most participants who were Hp-positive at baseline and Hp-negative at follow-up had reduced severity of active, chronic, and/or atrophic gastritis at follow-up. Though follow-up numbers are small, these results yield evidence that successful Hp treatment has the potential to reduce the risk of gastric cancer in Arctic Indigenous communities.

Real-World Practice of Gastric Cancer Prevention and Screening Calls for Practical Prediction Models

INTRODUCTION

Some gastric cancer prediction models have been published. Still, the value of these models for application in real-world practice remains unclear. We aim to summarize and appraise modeling studies for gastric cancer risk prediction and identify potential barriers to real-world use.

METHODS

This systematic review included studies that developed or validated gastric cancer prediction models in the general population.

RESULTS

A total of 4,223 studies were screened. We included 18 development studies for diagnostic models, 10 for prognostic models, and 1 external validation study. Diagnostic models commonly included biomarkers, such as Helicobacter pylori infection indicator, pepsinogen, hormone, and microRNA. Age, sex, smoking, body mass index, and family history of gastric cancer were frequently used in prognostic models. Most of the models were not validated. Only 25% of models evaluated the calibration. All studies had a high risk of bias, but over half had acceptable applicability. Besides, most studies failed to clearly report the application scenarios of prediction models.

DISCUSSION

Most gastric cancer prediction models showed common shortcomings in methods, validation, and reports. Model developers should further minimize the risk of bias, improve models' applicability, and report targeting application scenarios to promote real-world use.

Incidence Trends of Gastric Cancer in Southern Iran: Adenocarcinoma and Non-cardia Gastric Cancer Are More Rising Among Younger Ages

BACKGROUND

Gastric Cancer (GC) is still one of the major causes of cancer mortality. Due to health-related transitions, the epidemiology of GC subtypes may change. These changes may have profound effects on clinical approaches as well as on public health management of GC. Iran, as a developing country, has experienced huge demographic and epidemiological transitions during the recent decades. This study aimed to investigate the subtype-specific population-based incidence trends of GC in southern Iran.

METHODS

We used data on GC incidence in southern Iran during 2001-2015. Data preparation and subtype grouping were done based on the ICD-O-3. The trends of Age-Standardized incidence Rate (ASR), truncated ASRs, incidence rate of adenocarcinoma, and cardia GC, and age-gender specific rates were analyzed using joinpoint regression modeling. Annual Percentage Change (APC) and its 95% Confidence Intervals (CIs) were estimated.

RESULTS

Overall APC was estimated as 7.2 for males and 8.7 for females. The estimated APCs for the trends of overall GC, and gastric adenocarcinoma were stable in both genders during 2009-2015. Nonetheless, cardia GC showed increasing trends in both genders. The estimated APCs for the trends of non-cardia GC was also stable.

CONCLUSION

The overall trends of the GC incidence in southern Iran were stable during the past decade. However, significant and different changes have occured in the pattern of GC. Thus, etiological and prognostic studies are needed for the improvement of GC management in Iran.

Risk of gastric cancer in chronic obstructive pulmonary disease

OBJECTIVE

Owing to the potential role of the gut-lung axis in carcinogenesis, we assessed the incidence of gastric cancer in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Using Quebec's administrative databases, we assembled a cohort of 118 913 patients aged 40 years and older with COPD from 1995 to 2015. We calculated age-standardized incidence rate ratio (IRR) and 95% confidence interval (CI) for gastric cancer, comparing patients with COPD to the Quebec general population. We evaluated temporal changes in incidence by calculating annual percentage change (APC) and stratified the analysis by anatomical site.

RESULTS

Between 1995 and 2015, 279 patients with COPD developed gastric cancer (54.0 cases per 100 000 person-years). The overall age-standardized incidence rate in patients with COPD was comparable to the general population (IRR, 1.05; 95% CI, 0.79-1.39). However, the IRR increased over time (APC, 4.40%; P = 0.0101), due to the growing rate of gastric cancer in patients with COPD (APC, 1.90%; P = 0.2666) and the declining rate in the Quebec population (APC, -2.40%; P < 0.0001).

CONCLUSIONS

The overall risk of gastric cancer in patients with COPD did not differ from the general population; however, the risk among patients has increased over the years. These findings provide insights as to whether long-term follow-up for gastric cancer risk in COPD is warranted.

Climate Change and Enteric Infections in the Canadian Arctic: Do We Know What’s on the Horizon?

The Canadian Arctic has a long history with diarrheal disease, including outbreaks of campylobacteriosis, giardiasis, and salmonellosis. Due to climate change, the Canadian Arctic is experiencing rapid environmental transformation, which not only threatens the livelihood of local Indigenous Peoples, but also supports the spread, frequency, and intensity of enteric pathogen outbreaks. Advances in diagnostic testing and detection have brought to attention the current burden of disease due to Cryptosporidium, Campylobacter, and Helicobacter pylori. As climate change is known to influence pathogen transmission (e.g., food and water), Arctic communities need support in developing prevention and surveillance strategies that are culturally appropriate. This review aims to provide an overview of how climate change is currently and is expected to impact enteric pathogens in the Canadian Arctic.

Geographical variation and factors associated with gastric cancer in Manitoba

Objectives

We investigated the spatial disparities and factors associated with gastric cancer (GC) Incidence in Manitoba.

Methods

We combined information from Manitoba Cancer registry and Census data to obtain an age-sex adjusted relative risk (IRR) of GC incidence. We geocoded the IRR to the 96 regional health authority districts (RHADs) using the postal code conversion file (PCCF). Bayesian spatial and spatio-temporal Poisson regression models were used for the analysis.

Results

Adjusting for the effect of socio-economic score index (SESI), Indigenous, and immigrant population, 25 districts with high overall GC risk were identified. One unit increase in SESI was associated with reduced risk of cardia GC (CGC) by 14% (IRR = 0.859; 95% CI: 0.780–0.947) and the risk of non-cardia GC (NCGC) by approximately 10% (IRR = 0.898; 95% CI: 0.812–0.995); 1% increase in regional Indigenous population proportion reduced the risk of CGC by 1.4% (IRR = 0.986; 95% CI: 0.978–0.994). In the analysis stratified by sex, one unit increase in SESI reduced the risk of CGC among women by 26.2% (IRR = 0.738; 95% CI: 0.618–0.879), and a 1% increase in Indigenous population proportion reduced the risk of CGC among women by 1.9% (IRR = 0.981; 95% CI: 0.966–0.996).

Conclusion

Our results support a significant association between SESI and NCGC. We report regional variation of GC IRR and a varying temporal pattern across the RHADs. These results could be used to prioritize interventions for regions with high and progressive risk of GC.

Helicobacter pylori Infection

Helicobacter pylori infection remains one of the most prevalent infections worldwide, causing significant morbidity and mortality from gastric malignancies and peptic ulcers. This article provides a summary of the microbiology and pathogenesis of this bacterium, emphasizing the complex and protean effects of H pylori on gastric epithelial cells, including stem and progenitor populations, and evasion of host immune defenses. Increasing antibiotic resistance has made management more challenging. This article discusses the appropriate diagnostic modality for different clinical scenarios, and the evolving treatment of H pylori infections, including the use of antibiotic susceptibility testing to aid regimen selection.

Geographic and Socioeconomic Disparity of Gastric Cancer Patients in Canada

Gastric cancer is the 5th most common malignancy worldwide, representing ~5–10% of all new cancer cases. Although its incidence is declining, it is estimated that 1 in 98 Canadians will develop gastric cancer in their lifetime. The epidemiology and distribution of gastric cancer throughout Canada, however, remains poorly understood. A retrospective analysis of demographic data across Canada between 1992 and 2010 was performed using 2 population-based cancer registries. The incidence of gastric cancer was examined at the levels of provinces, cities, and postal codes. In addition, 43,955 patients were diagnosed with gastric cancer in Canada between 1992 and 2010; 66% were male and the average age of diagnosis was 68.4 years. The age-adjusted incidence rate was 5.07 cases per 100,000 individuals per year. The incidence decreased over the study period by 30%. High incidence rates were identified in rural areas of Newfoundland and Labrador, New Brunswick, and Quebec. Our study found a significant association between gastric cancer incidence rates and lower socioeconomic status, as well as Hispanic ethnicity. This is the first study to provide a comprehensive analysis of the incidence of gastric carcinoma in Canada, identifying high-risk populations that may benefit from increased primary and secondary prevention.

Stomach Cancer Incidence and Mortality Trends among Circumpolar Nations

BACKGROUND

Stomach cancer incidence and mortality rates are declining across circumpolar nations, but the burden may not be distributed equally across subpopulations, including Indigenous peoples. Our objective was to examine stomach cancer incidence and mortality trends across circumpolar populations.

METHODS

Cancer incidence and mortality data from 1999-2016 were obtained from the Canadian Cancer Registry, Canadian Vital Statistics, CDC WONDER, NORDCAN, Northwestern Russian cancer registries, and National Cancer Reports. The direct method was used to calculate 10-year rolling age-standardized incidence and mortality rates to the world (WHO 2000-2025) and 2011 Canadian standard populations. Standardized incidence rate ratios (SRR) were calculated. Data were stratified by sex, year, and region. U.S. data were broken down by race [White; American Indian/Alaska Native (AIAN)]. Race data were not available from non-U.S. cancer registries.

RESULTS

Most populations showed declining incidence and mortality rates over time. Incidence rates among Greenland males and females, Alaska AIAN males and females, and Northern Canadian both sexes were elevated compared with regional counterparts and remained stable. The largest male SRR was observed among Alaska AIAN versus Alaska Whites [SRR = 3.82; 95% confidence interval (95% CI), 2.71-5.37]. The largest female SRR was observed among Alaska AIAN versus Alaska Whites (SRR = 4.10; 95% CI, 2.62-6.43).

CONCLUSIONS

Despite stomach cancer incidence and mortality rates declining overall, some northern and Indigenous populations experience elevated and stable incidence and mortality rates.

IMPACT

There is a need to address disparities observed among circumpolar subpopulations. Given similarities in incidence, mortality, and risk factor prevalence across circumpolar regions, addressing disparities could benefit from coordinated international action.

Combating Gastric Cancer in Alaska Native People: An Expert and Community Symposium

Alaska Native (AN) people experience higher incidence of, and mortality from, gastric cancer compared to other U.S. populations1 , 2 . Compared to the general U.S. population, gastric cancer in AN people occurs at a younger age, is diagnosed at later stages, is more evenly distributed between the sexes, and is more frequently signet-ring or diffuse histology3 . It is known that the prevalence of Helicobacter pylori (Hp ) infection, a risk factor for gastric cancer, is high in AN people4 ; however, high antimicrobial resistance combined with high reinfection rates in Alaska make treatment at the population level complex5 . In addition, health issues in AN people are uniquely challenging due to the extremely remote locations of many residents.

A multiagency workgroup hosted a symposium in Anchorage that brought internationally-recognized experts and local leaders together to evaluate issues around gastric cancer in the AN population. The overall goal of this symposium was to identify the best strategies to combat gastric cancer in the AN population through prevention and early diagnosis.