Definition
Gastric cancer is a malignant tumor of the stomach, with ~90% being adenocarcinomas. It can present as polypoid, ulcerative, infiltrative, or diffuse (linitis plastica) types. It often arises on the background of chronic gastritis or intestinal metaplasia.
Etiology / Risk Factors
- Helicobacter pylori infection (most common risk factor worldwide)
- Chronic atrophic gastritis (especially with intestinal metaplasia)
- Autoimmune atrophic gastritis → pernicious anemia
- Gastric polyps (esp. adenomatous type)
- Gastric ulcer (especially non-healing)
- Family history / Genetic predisposition
- Diet: Smoked/salted foods, nitrosamines, low fresh produce
- Smoking, alcohol
Pathogenesis
- 1. Chronic inflammation (esp. by H. pylori) → mucosal injury
- 2. Progression to atrophic gastritis → intestinal metaplasia → dysplasia
- 3. Malignant transformation into adenocarcinoma
- 4. Tumor invades through gastric wall and metastasizes via:
- Lymphatics: regional and distant nodes (e.g., Virchow’s node)
- Hematogenous spread: especially to liver, lungs
- Transcoelomic spread: to peritoneum → ascites
Symptoms / Clinical Manifestations
Early stage (often asymptomatic)
- Nonspecific:
- Postprandial fullness or discomfort
- Mild epigastric pain
- Loss of appetite, fatigue
- Weight loss
- Anemia-related symptoms (tachycardia, pale skin, polished tongue)
Advanced stage
- Persistent epigastric pain
- Dysphagia (proximal tumors)
- Nausea, vomiting
- Gastrointestinal bleeding
- Palpable epigastric mass or lymph nodes (e.g., Virchow’s node)
- Cachexia, ascites, jaundice
- Signs of metastases:
- Liver: hepatomegaly, intrahepatic cholestasis, jaundice, itching
- Peritoneum: ascites
- Lungs: dyspnea, pleuritis, “mantle pneumonia”
- Pancreas: pancreatitis