Gastric Cancer

Basics

Description

  • Malignant neoplasm occurring in the stomach
  • Infiltration to lymph nodes, omentum, lungs, and liver is rapid.
  • Uncommon in U.S. natives
  • Synonym(s): linitis plastica (“leather bottle stomach”)

Pediatric Considerations
Rare

Pregnancy Considerations

  • Rarely diagnosed during pregnancy
  • Prognosis is poor.

Epidemiology

  • Predominant age: >55 years (2/3 are >65 years)
  • Predominant gender: male > female (1.7:1)
  • Incidence is decreasing globally but remains the fifth most common malignancy and the third leading cause of cancer death worldwide.

Incidence

  • 5.9/100,000 males (North America)
  • 2.5/100,000 females (North America)
  • 24,590 new cases per year (United States)

Etiology and Pathophysiology

Helicobacter pylori–associated gastric cancers are associated with interactions between bacterial virulence factors and host inflammatory responses.

Genetics

  • More common in people with blood group A
  • 2 to 4 times more common in first-degree relatives
  • 1–3% of gastric cancers are associated with inherited gastric cancer predisposition syndromes (hereditary diffuse gastric cancer [CDH1] gene).
  • Amplification or overexpression of the HER2 protein is associated with some gastric cancers.

Risk Factors

  • H. pylori infection is primary risk in 65–80%.
  • Smoking/tobacco abuse is second leading risk factor.
  • Diet rich in additives (e.g., smoked, pickled, or salted foods; highly spiced foods), nitrates, and nitrites have been implicated.
  • Atrophic gastritis/intestinal metaplasia
  • Pernicious anemia
  • Preexisting diabetes mellitus
  • Overweight and obesity: Strength of association increases with increasing body mass index (BMI).
  • Certain hereditary syndromes (familial adenomatous polyposis, hereditary nonpolyposis colon cancer, Peutz-Jeghers syndrome)
  • Barrett esophagus
  • Patients in lower socioeconomic status have higher risk of gastric cancer.
  • Low consumption of fruits and vegetables
  • Ethnicity: Hispanic, Japanese, Chilean, Costa Rican
    • Migrants from high-incidence areas (e.g., Iceland, Chile, or Japan) to low-incidence areas maintain an increased risk, whereas their offspring have an occurrence rate that corresponds to that of the new location.

General Prevention

  • Avoid tobacco, engage in regular exercise, maintain optimal body weight, and maintain a healthy diet.
    • Diets that include 5 to 20 servings of both fruits and vegetables each week reduce the risk of gastric malignancy by ~50%.
  • Insufficient data to recommend routine gastric cancer screening
  • Screening to identify and eradicate H. pylori may reduce the risk. The impact may be greatest with increasing age and in high-prevalence areas.

Commonly Associated Conditions

  • Giant hypertrophic gastritis (Ménétrier disease)
  • Intestinal metaplasia
  • Atrophic gastritis
  • H. pylori infection

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