- Clinical science
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.
- Exogenous risk factors
Endogenous risk factors
- Diseases associated with a higher risk of gastric cancer
- Hereditary factors (positive family history, hereditary non‑polyposis colorectal cancer)
- Higher incidence in individuals with blood type A.
Gastric cancer is often asymptomatic. Early signs are nonspecific and often go unnoticed. At later stages the following symptoms may occur:
- General signs
- Gastrointestinal signs
Late stage gastric cancer
- Palpable tumor in epigastric region
- Hepatomegaly, ascites
- Virchow's node: left supraclavicular adenopathy, located where the thoracic duct joins the subclavian vein at the venous angle.
- Sister Mary Joseph's node: umbilical node indicating metastasis from a gastrointestinal or abdominopelvic malignancy
- Malignant acanthosis nigricans (in particular associated with gastric adenocarcinoma)
- Lymphangitic spread
- Hematogenous spread: liver, lung, skeleton, brain
- Local invasion of adjacent structures
- Direct seeding
- 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
- Abdominal ultrasound
- Abdominal and pelvic CT-scan using intravenous and oral contrast;
- Thoracic CT-scan
- Diagnostic laparoscopy
- Adenocarcinoma (90% of cases)
Signet ring cell carcinoma
- Diffuse growth
- Multiple signet ring cells = round cells filled with mucin, with a flat nucleus in the cell periphery
- Less common
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)
- Exact therapy, which may be either curative or palliative, depends on staging and the type of tumor.
Radical gastrectomy and lymphadenectomy (operative standard)
- Resection of the lesser and greater omentum and radical lymphadenectomy
Roux-en-Y gastric bypass
- The surgeon separates the proximal jejunum from the duodenum and creates an end-to-end anastomosis of the jejunum with the remaining part of the stomach (gastrojejunostomy), or in the case of a total gastrectomy, with the esophagus (esophagojejunostomy).
- Duodenal stump is connected distally with the jejunum using an end-to-side anastomosis.
- Alternative: subtotal gastrectomy
- 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
Related to resorption
Related to anastomosis
Small intestinal bacterial overgrowth (SIBO)
- Definition: bacterial overgrowth within the small intestine
- Pathophysiology: bacterial overgrowth → bacteria deconjugate bile acids, increase vitamin B12 turnover, and produce increased amounts of vitamin K and folic acid
- Clinical features: diarrhea, steatorrhea, weight loss, malabsorption (e.g., deficiency of vitamin B12, A, E, D, zinc, and iron)
- Treatment: antibiotics and parenteral supplementation of vitamins and proteins, possibly surgical treatment
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.
- Cause: rapid emptying of undiluted chyme into the small intestine caused by a dysfunctional or bypassed pyloric sphincter
- 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.
- Cause: postprandial hypoglycemia; dysfunctional pyloric sphincter → chyme containing glucose immediately reaches the small intestine → glucose is quickly resorbed → hyperglycemia → excessive release of insulin → hypoglycemia and release of catecholamines
- Dietary modifications
- Octreotide and surgery are second and third-line therapies
- Early dumping
We list the most important complications. The selection is not exhaustive.
- 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.