Cancer Risk Reduction and Pathophysiology

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Questions and Answers

What is the expected outcome of pylori eradication, especially when achieved before irreversible pre-neoplastic changes have developed?

Increased risk of cancer development

Delayed onset of cancer development

No effect on cancer development

Reduced risk of cancer development (correct)

Which of the following dietary factors may contribute to gastric cancer risk?

Diets high in omega-3 fatty acids

Diets rich in fresh fruits and vegetables

Diets lacking vitamins C and A

Diets rich in salted, smoked or pickled foods (correct)

What is the common genetic abnormality associated with gastric cancer?

Mutations of the BRCA1 gene

Mutations of the E-cadherin (CDH1) gene

No predominant genetic abnormality (correct)

Mutations of the TP53 gene

What is the most common type of gastric cancer?

Adenocarcinoma Signup and view all the answers

What is the characteristic of intestinal carcinomas?

They arise from areas of intestinal metaplasia with histological features reminiscent of intestinal epithelium Signup and view all the answers

What is the common location of gastric cancers in the developing world?

Antrum, gastric body, and cardia Signup and view all the answers

What is the reason for the changing pattern of gastric cancer in Western populations?

Changes in lifestyle Signup and view all the answers

What is the characteristic of diffuse cancers?

They are poorly differentiated and occur in younger patients Signup and view all the answers

What is the approximate incidence of gastric carcinoma in males in the UK?

12/100 000 Signup and view all the answers

What is the estimated percentage of gastric cancer cases attributed to H. pylori infection?

60-70% Signup and view all the answers

What is the typical age range for the sharp rise in incidence of gastric carcinoma?

After 50 years Signup and view all the answers

What is the primary factor that influences the prognosis of gastric carcinoma?

Early detection of tumours Signup and view all the answers

Which of the following is a pathogenic factor in gastric carcinoma?

All of the above Signup and view all the answers

What is the approximate 5-year survival rate for gastric carcinoma?

Less than 30% Signup and view all the answers

What is the relationship between H. pylori infection and gastric acid secretion in most individuals?

H. pylori infection increases acid secretion Signup and view all the answers

What is the geographic region with the highest incidence of gastric carcinoma?

China, Japan, and Korea Signup and view all the answers

What is the primary treatment for low-grade gastric lymphoma confined to the superficial layers of the gastric wall?

H.pylori eradication and close observation Signup and view all the answers

What is the characteristic of gastrointestinal stromal cell tumours (GIST)?

They are usually benign and asymptomatic Signup and view all the answers

What is the prognostic factor for gastric lymphoma?

Stage I or II disease Signup and view all the answers

What is the role of EUS in gastric lymphoma?

To accurately define the depth of invasion into the gastric wall Signup and view all the answers

What is the treatment for high-grade B-cell lymphomas?

Rituximab, chemotherapy, surgery, and radiotherapy Signup and view all the answers

What is the characteristic of extranodal marginal zone lymphomas of MALT type?

They are closely associated with H.pylori infection Signup and view all the answers

What is the chromosomal translocation found in 25% of gastric lymphomas?

t(11 : 18) Signup and view all the answers

What is the pre-operative treatment for very large GISTs?

Imatinib to reduce the size of the tumour Signup and view all the answers

Study Notes

Gastric Carcinoma

Gastric carcinoma is the fourth leading cause of cancer death worldwide, with marked geographical variation in incidence.
Highest incidence rates are found in China, Japan, Korea, Eastern Europe, and parts of South America, with rates of 40/100,000 males.
In the UK, the incidence rate is 12/100,000 for men, and 50% lower in women.
Incidence rises sharply after 50 years of age.

Pylori Eradication and Cancer Prevention

Pylori eradication, especially before irreversible pre-neoplastic changes, reduces cancer risk in high-risk populations and is cost-effective.
Diets rich in salted, smoked, or pickled foods and consumption of nitrites and nitrates may increase cancer risk.

Pathophysiology of Gastric Cancer

Virtually all gastric cancers are adenocarcinomas arising from mucus-secreting cells in the base of gastric crypts.
Most develop upon a background of chronic atrophic gastritis with intestinal metaplasia and dysplasia.
Cancers are either ‘intestinal’, arising from areas of intestinal metaplasia, or ‘diffuse’, arising from normal gastric mucosa.

Distribution of Gastric Cancers

In the developing world, 50% of gastric cancers develop in the antrum, 20-30% in the gastric body, and 20% in the cardia.
In Western populations, proximal gastric tumours are becoming more common than those arising in the body and distal stomach.

Gastric Lymphoma

H. pylori infection is closely associated with the development of low-grade lymphoma (extranodal marginal zone lymphomas of MALT type).
EUS plays an important role in staging these lesions by accurately defining the depth of invasion into the gastric wall.

Treatment of Gastric Lymphoma

Initial treatment of low-grade lesions confined to the superficial layers of the gastric wall consists of H. pylori eradication and close observation.
High-grade B-cell lymphomas require a combination of rituximab, chemotherapy, surgery, and radiotherapy.

Prognosis of Gastric Cancer

The overall prognosis is poor, with less than 30% surviving 5 years.
The best hope for improved survival lies in more efficient detection of tumours at an earlier stage.

Other Tumours of the Stomach

Gastrointestinal stromal cell tumours (GIST) arise from the interstitial cells of Cajal and are occasionally found at upper gastrointestinal endoscopy.
These tumours are usually benign and asymptomatic but may occasionally be responsible for dyspepsia, ulceration, and gastrointestinal bleeding.