• Clinical science

Gastric cancer

Summary

Gastric cancer refers to neoplasms in the stomach, including cancers of the esophagogastric junction. The incidence is declining in the United States and Europe, while it is rising in Japan and South Korea. Gastric cancer is associated with several risk factors (e.g., consumption of foods high in nitrates, increased nicotine intake, Helicobacter pylori infection). In its early stages, the disease is often asymptomatic or accompanied by nonspecific symptoms (e.g., epigastric discomfort, postprandial fullness, or nausea). Late-stage disease may present with gastric outlet obstruction (mechanical obstruction of the pyloric canal), leading to weight loss and vomiting. Biopsy during endoscopy confirms the diagnosis. Adenocarcinomas are the most common form of gastric cancer. Treatment includes endoscopic or surgical resection. Depending on staging, chemotherapy may be indicated before or after surgery (neoadjuvant or adjuvant chemotherapy), or as a palliative therapy.

Epidemiology

  • Sex: >
  • Peak incidence: 70 years
  • Geographical distribution: strong regional differences
    • High incidence in South Korea and Japan
    • Declining incidence in the United States and Europe


References:[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

  • Exogenous risk factors
    • Diet rich in nitrates and/or salts (e.g., dried, preserved food)
    • Nicotine use
    • Low socioeconomic status
  • Endogenous risk factors

References:[1][3][4][5][6]

Clinical features

Gastric cancer is often asymptomatic. Early signs are nonspecific and often go unnoticed. At later stages the following symptoms may occur:

Subtypes and variants

Metastatic Disease

Diagnostics

Diagnostic procedures

  • Upper endoscopy with biopsy (best initial test) : Biopsy confirms the diagnosis
  • Barium upper GI series may be considered and would show loss of intestinal folds and stenosis

Laboratory test

Staging

  • Abdominal ultrasound
  • Endosonography
  • Abdominal and pelvic CT-scan using intravenous and oral contrast;
  • Thoracic CT-scan
  • Diagnostic laparoscopy

Staging of gastric cancer is essential to determine the correct treatment options. When first diagnosed with gastric cancer, ∼ 70% of patients already show metastatic spread to the lymph nodes!

References:[7][8][9][10]

Pathology

Lauren classification of gastric adenocarcinoma

  • Intestinal type (∼ 50% of cases): polypoid, glandular formation; expanding (not infiltrative) growth pattern; clear border
  • Diffuse type (∼ 40% of cases): infiltrative growth and diffuse spread in the gastric wall, no clear border
  • Mixed type (∼ 10% of cases)

References:[7][11]

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

  • Exact therapy, which may be either curative or palliative, depends on staging and the type of tumor.
    • Endoscopic resection
    • Surgery
    • Perioperative chemotherapy, sometimes radiotherapy
    • Trastuzumab is indicated for HER2+ gastric adenocarcinomas

Surgery

  • Radical gastrectomy and lymphadenectomy (operative standard)
  • Alternative: subtotal gastrectomy

References:[12]

Complications

Malignant acanthosis nigricans

  • A paraneoplastic syndrome seen in adenocarcinomas of GI origin, especially in gastric adenocarcinoma
  • Pathophysiology: caused by exogenous transforming growth factor TGF-α and epidermal growth factor (GF)
  • Clinical findings
    • Brown to black, intertriginous and/or nuchal hyperpigmentation that can turn into itching, papillomatous, poorly-defined efflorescence
    • Rapid growth and verrucous or papulous surface helps to differentiate it from benign acanthosis nigricans
    • Localization: axilla, groin, neck

Malignant acanthosis nigricans always requires further diagnostic measures to look for malignancy!

Postgastrectomy syndromes

Related to resorption

Related to anastomosis

Related to motility

  • Dumping syndrome: rapid gastric emptying due to either defective gastric reservoir function or pyloric emptying mechanism, or anomalous postsurgery gastric motor function.
    • Early dumping
      • Cause: rapid emptying of undiluted chyme into the small intestine caused by a dysfunctional or bypassed pyloric sphincter
      • Clinical features
        • Appears within 15–30 minutes after ingestion of a meal
        • Symptoms may include nausea, vomiting, diarrhea, and cramps, as well as 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 to cover protein and energy requirements are preferable.
        • 30–60 min of rest in the supine position after meals
        • Often spontaneous improvement after a couple of months
    • Late dumping
      • Cause: postprandial hypoglycemia; dysfunctional pyloric sphincterchyme containing glucose immediately reaches the small intestine → glucose is quickly resorbed → hyperglycemia → excessive release of insulinhypoglycemia and release of catecholamines
      • Treatment
        1. Dietary modifications
        2. Octreotide and surgery are second and third-line therapies

Suspect late dumping syndrome in a patient with previous gastric surgery and hypoglycemia!

Remnant carcinoma is a complication associated with the remnant stomach. Follow-up is important!References:[13][14][15]

We list the most important complications. The selection is not exhaustive.

Prognosis

  • Since there are no early signs, gastric cancer is often diagnosed very late. At diagnosis, 60% of cancers have already reached an advanced stage that does not allow for curative treatment.
    • Early gastric cancer has the best prognosis .
    • Distant metastases or peritoneal carcinomatosis dramatically worsen the prognosis and are lethal most of the time.