3. Gastric Cancer Epidemiology Forth common types of cancer Second most common cancer related death Geographic variations (ten times) Continuing decline Primarily a decline of distal GC (2000) (2000)
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6. Gastric Cancer Environmental factors H. pylori Genetic factors Etiological Factors of Gastric Cancer Precancerous changes
38. 08/19/11 Gastric adenocarcinoma is a malignant epithelial tumor, originating from glandular epithelium of the gastric mucosa. According to Lauren classification, gastric adenocarcinoma may be: intestinal type, diffuse type and mixed type
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40. Gastric cancer. A, Intestinal type demonstrating gland formation by malignant cells, which are invading the muscular wall of the stomach. (H & E.) B, Diffuse type demonstrating individual red, mucin-containing malignant cells in the lamina propria of an intact mucosa. (Mucicarmine stain.)
51. Clinical manifestation Signs and Symptoms Early Gastric Cancer Asymptomatic or silent 80% Peptic ulcer symptoms 10% Nausea or vomiting 8% Anorexia 8% Early satiety 5% Abdominal pain 2% Gastrointestinal blood loss <2% Weight loss <2% Dysphagia <1%
52. Signs and Symptoms Advanced Gastric Cancer Weight loss 60% Abdominal pain 50% Nausea or vomiting 30% Anorexia 30% Dysphagia 25% Gastrointestinal blood loss 20% Early satiety 20% Peptic ulcer symptoms 20% Abdominal mass or fullness 5% Asymptomatic or silent <5% Duration of symptoms Less than 3 month 40% 3-12 months 40% Longer than 12 month 20%
This regional difference has been attributed to environmental factors. There is a continuing worldwide decline in prevalence and death rate. The reduction in the incidence of gastric carcinoma may reflect primarily a decline in carcinomas of the distal stomach.
The development of gastric cancer is a multi-factor process. A large number of risk factors have been associated with gastric cancer. These include dietary factor, smoking, H. pylori infection, low gastric acidity, genetic factors. Excessive intake of salt or salty food, low consumption of fresh fruits and vegetables are likely contribute to the development of gastric cancer. Studies had indicated there was a significant association between cigarette smoking and gastric cancer risk, particularly in male smokers. H. pylori is a definite carcinogen accounting for at least 300 000 new cases of gastric cancer each year worldwide. Familiar studies have found that the risk of developing gastric cancer for relatives of cases is increased two- to three-fold suggesting a role of genetic factors. Low gastric acidity may increase intraluminal formation of N-nitroso compounds which are carcinogens.