Gastric Cancer: Screening Methodology and Future Directions

Authored By: Carissa Nair

Non-cardia gastric cancer, or cancer originating in the distal regions of the stomach, is the fifth most common form of cancer worldwide. In 2020, as many as one million new cases and 770,000 new deaths were reported across the world [1]. Within the United States, regional, racial, and ethnic disparities influence incidence and risk. More specifically, Black, Hispanic, and Asian and Pacific Islander populations have shown consistently higher rates of incidence and mortality, despite the overall decrease in the diagnosis of this disease [2].  Primary prevention strategies for gastric cancer include screening for precursors–such as H. Pylori, a bacterial infection, intestinal metaplasia, and other lifestyle and dietary considerations. This article will evaluate the functionality and efficacy of the aforementioned screening methods.

H. Pylori is a bacterial infection that can result in inflammation of the stomach lining, a condition also known as gastritis. H. Pylori-associated gastritis is linked to nearly 75% of gastric cancers, making it a widely-used risk-prediction measure for non-cardia gastric cancer in a variety of research and screening studies [3]. Furthermore, this infection can be asymptomatic, necessitating effective detection and diagnostic methodology. Virulence factors transmitted via H. Pylori include VacA, a cytotoxin that impairs the DNA-repair capabilities of host cells. As a consequence, oncogenes can be activated and tumor suppressor genes, typically involved in preventing uncontrolled cell division and replication, deactivated, both of which are key elements in the pathogenesis of gastric cancer [4]. There are several tests that allow for early H. Pylori detection, including stool tests that permit microbiome profiling and blood tests, designed to detect IgG antibodies. Once detected, H. Pylori can be treated effectively with antibiotics, including Pylera and Metronidazole, which are prescribed on the basis of a patient’s resistance profile. This information was used as the foundation for a gastric cancer prevention study in Houston, TX, at the Baylor Medical School’s Department of Gastroenterology–which I was able to participate in as a research intern this summer. 

In addition to H. Pylori screenings, which are categorized as a primary prevention strategy, secondary prevention strategies include diagnosing precancerous conditions like intestinal metaplasia, Barrett’s esophagus, and ulcers/polyps through involved procedures, including endoscopies and biopsies. Detecting any of the above conditions is associated with a 60-90% predictive rate for gastric cancer. According to a 2014 study by Ji and Li, ulcers prove to be the most conclusive in formulating a diagnosis [5]. Despite the effectiveness of these secondary prevention strategies, they are not necessarily accessible. Not only are these screening methods dependent on evaluation by specialists and physicians, but they are significantly more costly, time-consuming, and invasive. In addition to endoscopies, novel technology such as endocytoscopies, infrared spectroscopy, and laser endomicroscopy [5] have also proved useful in visualizing precancerous conditions, paving the way for future developments in effective screening and prevention.

Current research studies are focused on evaluating the efficacy of primary and secondary screening methods, with the aim of developing risk-prediction models that include data about dietary and lifestyle factors in addition to medical histories and diagnoses. In a 2022 meta-analysis performed by Bouras et al, unhealthy dietary choices and lifestyle index metrics were found to be associated with a higher risk of non-cardia gastric cancer [6]. Research on important precursors, such as H. Pylori and intestinal metaplasia have paved the way for more conclusive diagnostic testing and imaging. Moreover, ongoing research in this field focuses on developing a holistic evaluative model of screening, which can prove useful in addressing socio-demographic disparities and healthcare inaccessibility.

Works Cited 

1. Morgan, E., Arnold, M., Camargo, M. C., Gini, A., Kunzmann, A. T., Matsuda, T., Meheus, F., Verhoeven, R. H. A., Vignat, J., Laversanne, M., Ferlay, J., & Soerjomataram, I. (2022). The current and future incidence and mortality of gastric cancer in 185 countries, 2020–40: A population-based modelling study. eClinicalMedicine, 47. https://doi.org/10.1016/j.eclinm.2022.101404

2. Gonzalez-Pons, M., Torres-Cintrón, C. R., Soto-Salgado, M., Vargas-Ramos, Y., Perez-Portocarrero, L., Morgan, D. R., & Cruz-Correa, M. (2023). Racial/ethnic disparities in gastric cancer: A 15-year population-based analysis. Cancer medicine, 12(2), 1860–1868. https://doi.org/10.1002/cam4.4997

3. Polk, D. B., & Peek, R. M. (2010). Helicobacter pylori: Gastric cancer and beyond. Nature Reviews. Cancer, 10(6), 403–414. https://doi.org/10.1038/nrc2857

4. Salvatori, S., Marafini, I., Laudisi, F., Monteleone, G., & Stolfi, C. (2023). Helicobacter pylori and Gastric Cancer: Pathogenetic Mechanisms. International journal of molecular sciences, 24(3), 2895. https://doi.org/10.3390/ijms24032895

5. Ji, R., & Li, Y. Q. (2014). Diagnosing Helicobacter pylori infection in vivo by novel endoscopic techniques. World journal of gastroenterology, 20(28), 9314–9320. https://doi.org/10.3748/wjg.v20.i28.9314

6. Bouras, E., Tsilidis, K. K., Triggi, M., Siargkas, A., Chourdakis, M., & Haidich, A. B. (2022). Diet and Risk of Gastric Cancer: An Umbrella Review. Nutrients, 14(9), 1764. https://doi.org/10.3390/nu14091764