Gastroenterology Book

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Gastric CancerAka: Gastric Carcinoma, Stomach Cancer

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  1. Epidemiology
    1. Gender: More common in men
    2. Age: 40 to 70 years
  2. Pathophysiology
    1. Adenocarcinoma accounts for 95% of cases
    2. Atrophic Gastritis precedes metaplasia and malignancy
  3. Risk Factors
    1. Familial adenomatous polyposis
    2. Non-polyposis hereditary Colon Cancer
    3. Gastric adenoma
    4. Helicobacter Pylori (distal stomach tumors)
    5. Barrett's Esophagus (cardiac and esophageal border)
    6. Prior subtotal gastrectomy (after 15-20 years)
    7. Pernicious Anemia
    8. Tobacco abuse
    9. Chronic atrophic Gastritis
    10. Racial predisposition (twice as common as caucasians)
      1. Native americans
      2. Hispanic patients
      3. Black patients
  4. Symptoms
    1. Asymptomatic in early stages in 80% of cases
    2. Late stage symptoms
      1. Weight loss
      2. Nausea and Vomiting
      3. Abdominal Pain
      4. Early satiety
  5. Signs
    1. Palpable epigastric mass
    2. Hepatomegaly
    3. Lymphadenopathy (e.g. periumbilical or supraclavicular)
  6. Differential Diagnosis
    1. Peptic Ulcer Disease
    2. Gastroesophageal Reflux disease
  7. Radiology
    1. Double contrast barium swallow
      1. May be a cost effective for initial evaluation
  8. Diagnostic Testing
    1. Upper endoscopy (Esophogastroduodenoscopy or EGD)
      1. Best tool for gastric cancer diagnosis
      2. Sydney system recommends 5 biopsies
    2. Endoscopic ultrasonography (EUS)
      1. Used to stage gastric cancer
  9. Staging: TNM Classification
    1. Staging system
      1. Primary Tumor (T)
        1. TX: Cannot assess
        2. Tis: Carcinoma in situ
        3. T0 - T4: Increasing degrees of local tumor invasion
      2. Regional lymph nodes (N)
        1. NX: Cannot assess
        2. N0 - N3: Increasing degrees of lymph nodes involved
      3. Distant metastases (M)
        1. MX: Cannot assess
        2. M0: No metastases
        3. M1: Distant metastases
    2. Stages (Summary of AJCC Staging - not an exact list)
      1. Stage 0: Tis, N0, M0 (Carcinoma in-situ)
      2. Stage IA: T1, N0, M0 (Submucosa involved)
      3. Stage IB: T1-T2b, N0-N1, MO (subserosa involved)
      4. Stage II: T1-T3, N0-N2, M0 (visceral peritoneum)
      5. Stage IIIA: T2a-T4, N0-N2, M0 (local tumor invasion)
      6. Stage IIIB: T3, N2, M0 (7-15 lymph nodes involved)
      7. Stage IV: T1-T4, N1-N3, M0-1 (increased metastases)
  10. Management
    1. Radiation Therapy
      1. Modestly effective
    2. Chemotherapy
      1. Not effective as sole therapy
      2. Used as adjunct to surgery and radiation
    3. Surgery based on tumor location in stomach
      1. Cancer of proximal-third of stomach
        1. Gastrectomy with distal esophagus resected
      2. Cancer of middle-third of stomach
        1. Total gastrectomy
      3. Cancer of distal-third of stomach
        1. Intestinal adenocarcinoma: Subtotal gastrectomy
        2. Diffuse carcinoma: Total Gastrectomy
  11. Prognosis: Five year survival
    1. Stage O: 90%
    2. Stage I: <78%
    3. Stage II: 34%
    4. Stage III: <20%
    5. Stage IV: 7%
  12. Prevention
    1. Tobacco Cessation
    2. Dietary changes (possible benefit)
      1. Decrease Alcohol intake
      2. Decrease smoked, pickled or salted food intake
      3. Increase fruit and vegetable intake
    3. Aggressively treat and monitor associated conditions
      1. Barrett's Esophagus
      2. Atrophic Gastritis
      3. Helicobacter Pylori infection
    4. Screening EGD for high risk patients every 1-3 years
      1. See Risk factors above
  13. References
    1. Gunderson in Abeloff (2000) Oncology, p. 1545-79
    2. Toh in Feldman (2002) Sleisenger GI, p. 829-47
    3. Layke (2004) Am Fam Physician 69(5):1133

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