RELATIONSHIP BETWEEN GASTRIC CANCER AND HELICOBACTER PYLORI: A SYSTEMATIC REVIEW (Research Paper Sample)

RELATIONSHIP BETWEEN GASTRIC CANCER AND HELICOBACTER PYLORI: A SYSTEMATIC REVIEW By MPH S.T, Ph.D., MPH A Public Health Capstone Project Presented in Partial Fulfillment of the Requirements for the Degree Master of Public Health (Promotion) National University May 2023 Abstract As early as 17 October 1991 and writing in the New York Times, journalist Lawrence K. Altman run an article titled ‘Stomach Cancer Is Linked to Persistent Infection with a Common Bacterium’. The bacterium he was referring to is Helicobacter pylori. Stomach cancer is one of the second most common types of cancer in the world and if h. pylori is a risk factor, then this is something to worry about; or at best, make efforts to eradicate h. pylori. Other studies have also shown that people who are infected with H. pylori are also up to 8 times more likely to get a certain kind of stomach, or gastric, cancer. Available data however, is not clear about the severity of the risks as well as the mechanisms of action. This capstone project conducts a study to establish the relationship between gastric cancer and Helicobacter pylori. In particular, the study explores previous literatures on this issue to find out clear findings about the association in order to guide medical practice. Indeed, many physicians, clinical practitioners, and medical scientists have conducted studies to establish whether H. pylori is a risk factor for gastric cancer or causes gastric cancer. However, in terms of action and mechanisms, some studies show some variance. The study explores over 50 literatures from academic databases with peer reviewed studies, such as PubMed, CINAHL, National Library of Medicine, and National University Library. Other information is retrieved from Google Scholar and Science.gov. The study findings show that after endoscopic mucosal excision, there was a noticeably lower incidence of gastric cancer in the H. pylori group for patients with early-stage stomach cancer. In individuals with early-stage gastric cancer, the elimination of H. pylori is linked to a decreased risk of developing gastric cancer and improvements in atrophic gastritis and intestinal metaplasia. Patients with baseline intestinal metaplasia and atrophic gastritis had the same rate of gastric cancer. The prevalence of H. pylori in all ages was 57.57%. In retrospect, H. pylori is established as a risk factor for this malignancy. Table of Contents TOC \o "1-3" \h \z \u CHAPTER 1 – INTRODUCTION PAGEREF _Toc135483321 \h 7 Introduction to the Problem PAGEREF _Toc135483322 \h 7 The Problem PAGEREF _Toc135483323 \h 7 Purpose of the Study PAGEREF _Toc135483324 \h 8 Hypotheses or Research Question PAGEREF _Toc135483325 \h 8 Significance of the Study PAGEREF _Toc135483326 \h 8 Assumptions PAGEREF _Toc135483327 \h 8 Limitations PAGEREF _Toc135483328 \h 9 Summary PAGEREF _Toc135483329 \h 9 CHAPTER 2 – LITERATURE REVIEW PAGEREF _Toc135483330 \h 10 Description of Gastric Cancer PAGEREF _Toc135483331 \h 10 Statistics PAGEREF _Toc135483332 \h 14 Global Occurrence PAGEREF _Toc135483333 \h 15 Gastric Cancer PAGEREF _Toc135483334 \h 16 Symptoms of Gastric Cancer PAGEREF _Toc135483335 \h 17 H. pylori Infection and Gastric Cancer Among Adult U. S. Immigrants PAGEREF _Toc135483336 \h 18 Active Lifestyle and Gastric Cancer Prevention PAGEREF _Toc135483337 \h 19 CHAPTER 3 – METHODOLOGY PAGEREF _Toc135483338 \h 21 Databases used PAGEREF _Toc135483339 \h 21 Keyword Search PAGEREF _Toc135483340 \h 21 Inclusion and Exclusion Criteria PAGEREF _Toc135483341 \h 21 CHAPTER 4. Data Collection, Analysis and Results PAGEREF _Toc135483342 \h 23 Results PAGEREF _Toc135483343 \h 23 Data Analysis and Results PAGEREF _Toc135483344 \h 27 cag PAI PAGEREF _Toc135483345 \h 29 CagA PAGEREF _Toc135483346 \h 29 Peptidoglycan PAGEREF _Toc135483347 \h 31 Host Factors PAGEREF _Toc135483348 \h 31 Oxidative damage PAGEREF _Toc135483349 \h 32 CHAPTER 5: Conclusions and Recommendations PAGEREF _Toc135483350 \h 33 References PAGEREF _Toc135483351 \h 35 Acknowledgement CHAPTER 1 – INTRODUCTION Introduction to the Problem H. pylori, one of the leading causes of cancer-related death worldwide, are a known risk factor for acquiring Gastric cancer. Half of the world's population is afflicted with the pathogen H. pylori. Although most infected people have few symptoms, the infection can lead to gastritis, which can potentially develop into stomach cancer. Compared to U.S-born individuals, immigrants to the United States have a greater likelihood of passing away from gastric cancer, mainly due to factors before they migrated to the United States, such as diet and a pre-existing risk of H. pylori infection (Hallowell et al., 2019). The Problem Bacteria known as H. pylori can inflame the stomach after infection. Over time, this inflammation may pave the way for the emergence of stomach cancer. H. pylori and stomach cancer have a complicated and poorly understood association. However, evidence indicates that H. pylori may contribute to the occurrence of stomach cancer in some people. In 2021, gastric cancer mortality is estimated to be about 11,130, and approximately 26,500 new cases, 1.5% of all new cancers diagnosed in the United States (Wessel et al., 2022). Every year, around six out of every ten people diagnosed with stomach cancer are 65 or older, with an average age of 68. In addition, men have a higher lifetime risk of developing stomach cancer (about 1 in 96) than women (about 1 in 152). However, many other factors can influence each individual's risk (Wessel et al., 2022). Purpose of the Study This study investigates the relationship between adult H. pylori infections and stomach cancer among U.S. immigrants, mainly from Asian and African developing countries. The study also seeks to determine if leading an active lifestyle, for example, recreational sports, affects gastric cancer symptoms or prognosis. This study also aims to conduct a thorough literature review to investigate the relationship between adult U.S. immigrants from developing parts of the world's H. pylori infections and stomach cancer. In addition, the study seeks to determine how H. pylori impact the growth of stomach cancer cells in the body. Hypotheses or Research Question 1 What effect do H. pylori have on the formation of cancer cells in the stomach among adult U.S. migrants? 2 Does an active lifestyle promote fewer symptoms of gastric cancer causes and affect prognosis? Significance of the Study            This study's findings may help clarify the connection between H. pylori and stomach cancer, particularly among adult immigrants in the United States. Furthermore, understanding these problems makes it possible to develop methods for preventing and treating stomach cancer within the given population. Assumptions            It is assumed that the study participants cited are typical adult immigrants to the United States. Therefore, the information gathered will appropriately depict this population's association between stomach cancer and H. pylori. Limitations            The volume of currently available information and articles restrict the conclusions that may be drawn from this study. The study only included adult immigrants. Therefore, it might not be generalizable to other groups. Summary            This study uses a thorough literature analysis to examine the connection between adult immigrants' H. pylori infection and stomach cancer. In addition, the study will look at how H. pylori affect the development of stomach cancer cells and how an active lifestyle affects gastric cancer symptoms and prognosis. This study's findings may help improve knowledge of the association between gastric cancer and H. pylori within this population and may be applied to developing preventative and therapeutic methods for gastric cancer. CHAPTER 2 – LITERATURE REVIEW Description of Gastric Cancer Within the gastrointestinal system, the stomach is an unusual organ. Its part in food digestion depends on the function of the muscles, acids, and enzymes that guide the processes, as well as the tubular form of the organ. The stomach is comprised of several layers of tissue, including the muscular propria, serosa, and submucosa. It is partitioned into four segments: the cardia, pylorus, fundus, and body. Endocrine cells in the gastric antrum, a part mucous membrane in the pylorus , produce more than half of the hormone gastrin, which circulates the bloodstream to the human stomach (Sugano, 2019). Understanding the formation of stomach tumors and the progression of gastric malignancies depends on understanding the process of regeneration of the stomach cells. The expression "gastric cancer" describes cancer in the stomach's lining. Its causes are complicated, with a number of variables affecting its occurrence and prevalence. The bacterium H. pylori is closely linked to the onset of stomach cancer. In addition, although uncommon, tumors, including squamous cell carcinomas and adenosquamous carcinomas, can form in the stomach (Ford, Yuan & Moayyedi, 2020). Gastric adenocarcinoma originates in the stomach's mucosal layer and can advance through the lymphatic vessels to surrounding nodes, and it is the most widely recognized gastric tumor. Figure 1 shows the stomach’s layers. As shown in figure 1, and according to Jiang et al. (2019), the mucosa is the deepest layer, including the endocrine cells entrusted with secretion of gastrin. The serosa is the top layer. Figure 2 shows the pathogenesis of gastric cancer. When H. pylori interacts with stomach components, the pathogenesis process begins, and either atrophic or non-atrophic gastritis results. A duodenal ulcer might occur if the etiology does not progress to full-blown malignancy (Pormohammad et al., 2019). Figure 1. The Stomach’s layers Source: Jiang, K., Jiang, X., Wen, Y., Liao, L., & Liu, F...