Harvey's Garden

Gastric cancer

3 min read

Epidemiology

Etiology

Exogenous risk factors

  • Diet rich in nitrates and/or salts (e.g., dried foods, foods preserved by curing or smoking) and low in fresh vegetables containing antioxidants
    • Bacteria are believed to convert ingested nitrates into carcinogenic nitrites.
  • H. pylori infection
  • Nicotine use
  • Epstein-Barr virus

Endogenous risk factors

Pathophysiology

Two major histologic types

  • Intestinal Type
    • Resembles colonic adenocarcinoma; forms glandular structures.
    • Located typically on the lesser curvature of the antrum/pylorus.
    • Strong association with H. pylori, smoking, and nitrosamines.
  • Diffuse Type
    • Not associated with H. pylori.
    • Signet Ring Cells: Mucin-filled cells with nucleus pushed to the periphery.
    • Linitis Plastica: “Leather bottle” stomach due to diffuse infiltration and thickening of the stomach wall (loss of distensibility).
    • Younger patients; worse prognosis.

Clinical features

Diagnostics

Pathology

Gastric adenocarcinoma

  • Accounts for ∼ 95% of cases
  • Most commonly located on the lesser curvature

Lauren classification of gastric adenocarcinoma

  • Intestinal type gastric carcinoma
    • Typically localized
    • Polypoid, glandular formation
    • Similar to an ulcerative lesion with clear raised margins
    • Commonly located on the lesser curvature
    • Must be differentiated from peptic gastric ulcers by biopsy
  • Diffuse type gastric carcinoma
    • No clear border
    • Spreads earlier in the course of disease
    • Infiltrative growth
    • Diffuse spread in the gastric wall
    • Linitis plastica: gastric wall thickening and leather bottle appearance
    • Composed of signet ring cells: round cells filled with mucin, with a flat nucleus in the cell periphery
    • Associated with E-cadherin mutation
      • E-cadherin is a family of calcium-dependent glycoproteins that facilitate cell-to-cell adhesion at adherens junctions. Link to the actin cytoskeleton via catenin and vinculin.
      • Due to its role in cell adhesion and differentiation, E-cadherin protects against tumor formation. Low expression is associated with poorer prognosis (e.g., increased depth of invasion or severe lymph node involvement).

Treatment

Complications

Postgastrectomy complications

Dumping syndrome

  • Definition: rapid gastric emptying as a result of defective gastric reservoir function, impaired pyloric emptying mechanisms, or anomalous postsurgery gastric motor function

Early dumping

  • Pathophysiology: dysfunctional or bypassed pyloric sphincter → rapid emptying of undiluted hyperosmolar chyme into the small intestine → fluid shift to the intestinal lumen → small bowel distention → vagal stimulation → increased intestinal motility
  • Clinical features
    • Occur within 15–30 minutes after meal ingestion
    • Include nausea, vomiting, diarrhea, and cramps
    • Vasomotor symptoms such as sweating, flushing, and palpitations
  • Management
    • Dietary modifications: small meals that include a combination of complex carbohydrates and foods rich in protein and fat

Late dumping

  • Pathophysiology: dysfunctional pyloric sphincter → rapid emptying of glucose-containing chyme into the small intestine → quick reabsorption of glucose → hyperglycemia → excessive release of insulin → hypoglycemia and release of catecholamines
  • Clinical features
    • Occur hours after meal ingestion
    • Include signs of hypoglycemia (e.g., hunger, tremor, lightheadedness)
    • GI discomfort
  • Management
    • Dietary modifications
    • Second-line treatment: octreotide
    • Third-line treatment: surgery

Graph View

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