Gastric Cancer

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