Which infectious agent is a risk factor for the development of stomach cancer?

RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Medical & Surgical Nursing

Easy

Appeared in: RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Explanation

Helicobacter pylori colonization is the primary infectious risk factor for gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT) lymphoma.
The bacterium induces chronic superficial gastritis, a persistent inflammation that can progress to cancer over decades through a sequence of atrophic gastritis, intestinal metaplasia, and dysplasia.
The World Health Organization (WHO) classifies H. pylori as a Class I carcinogen, confirming its causal role in stomach cancer.
Certain bacterial virulence factors, such as CagA and VacA, are associated with strains that carry a higher risk of causing peptic ulcers and gastric cancer.

Option A: Escherichia coli is a common cause of gastrointestinal infections leading to diarrhea (e.g., traveler's diarrhea) and urinary tract infections. It does not cause the chronic gastric inflammation that leads to stomach cancer.
Option B: Salmonella species are responsible for food poisoning (gastroenteritis) and typhoid fever. These are typically acute infections and are not associated with the development of gastric malignancies.
Option D: Shigella is the causative agent of bacillary dysentery, an intestinal infection characterized by severe, often bloody, diarrhea. It does not colonize the stomach or cause gastric cancer.

Visual 1: Diagram: Illustrating the Correa cascade, the progression from normal gastric mucosa to chronic gastritis, atrophic gastritis, intestinal metaplasia, dysplasia, and finally gastric adenocarcinoma, initiated by H. pylori infection.
Visual 2: Micrograph: Showing Helicobacter pylori bacteria (curved rods) colonizing the gastric mucosal layer, often near the epithelial cells.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Infectious etiology of gastric cancer as background academic context rather than a clinical decision trigger.
Nurses play a crucial role in patient education regarding H. pylori, explaining the importance of completing the prescribed antibiotic regimen to eradicate the infection and reduce the long-term risk of peptic ulcers and stomach cancer.
In high-risk populations, a 'test-and-treat' strategy for H. pylori is a key public health measure for the primary prevention of gastric cancer.
What if? If a patient is diagnosed with early-stage gastric MALT lymphoma, the primary treatment is not chemotherapy but rather the eradication of H. pylori with antibiotics, which often leads to complete remission of the lymphoma.

How to Approach the Question

Identify the key concepts in the question: 'infectious agent' and 'stomach cancer'.
Analyze the options provided, all of which are bacteria known to cause gastrointestinal issues.
Differentiate the primary pathology of each bacterium. Recall that E. coli, Salmonella, and Shigella are primarily associated with acute intestinal infections like diarrhea and dysentery.
Recognize that Helicobacter pylori is uniquely adapted to survive in the acidic environment of the stomach and is known to cause chronic conditions.
Connect the concept of chronic inflammation with the risk of cancer. H. pylori's ability to cause decades-long chronic gastritis makes it the most plausible infectious agent for causing stomach cancer among the choices.

Concept Tested & Keywords

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