- 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.
- 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
Epidemiological data refers to the US, unless otherwise specified.
- 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.
|Tis||Carcinoma in situ: without invasion of basal membrane. No metastatic spread!|
|T1||Limited to mucosa (T1a) and submucosa (T1b) (does not penetrate the muscularis propria): T1 = early gastric cancer (metastatic spread possible!)|
|T2||Penetration of muscularis propria|
|T3||Penetration of subserosa|
|T4||Penetration of serosa (T4a), including penetration of adjacent structures (T4b)|
|N1||1–2 regional lymph nodes|
|N2||3–6 regional lymph nodes|
|N3||≥ 7 regional lymph nodes (N3a: 7–15 lymph nodes, N3b: > 15 lymph nodes)|
|M1||Distant metastases, peritoneal carcinomatosis|
This classification was proposed by Siewert and is applied in clinical practice.
|Type||Localization||Comments and surgical approaches|
|Center of the tumor located 1–5 cm above the z-line (associated with Barrett mucosa)|
|Siewert type II||Center of the tumor located 1 cm above or 2 cm below the z-line (true carcinoma of the cardia)|| |
|Siewert type III||Center of the tumor located 2–5 cm below the z-line (proximal gastric cancer diffused to cardia)|
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
UICC classification (Union for International Cancer Control)
|UICC stage||TNM classification of gastric cancer|
|Stage 0||Tis (Carcinoma in situ)|
|Stage IA||T1 N0 M0|
|Stage IB||T1 N1 M0|
|T2 N0 M0|
|Stage II||T1 N2 M0|
|T2 N1 M0|
|T3 N0 M0|
|Stage IIIA||T2 N2 M0|
|T3 N1 M0|
|T4 N0 M0|
|Stage IIIB||T3 N2 M0|
|Stage IV||T1-T3 N3 M0|
|T4 N1-3 M0|
|Tx Nx M1 (any distant metastases)|
- 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; sufficient oral contrast is required to fill the stomach
- 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)
- Gastric ulcer
- Gastroesophageal reflux disease (GERD)
- Ménétrier's disease
- Non-ulcer dyspepsia
- Other types of cancer
- MALT lymphoma
Gastrointestinal stromal tumor (GIST)
- Description: GIST is a malignant mesenchymal neoplasm of the gastrointestinal tract, resembling the intestinal cells of Cajal
- Clinical features
The differential diagnoses listed here are not exhaustive.
Principles of treatment
- Exact therapy, which may be either curative or palliative , depends on staging and the type of tumor.
- Endoscopic resection
- Perioperative chemotherapy, sometimes radiotherapy
- Trastuzumab is indicated for HER2+ gastric adenocarcinomas
Endoscopic resection of superficial gastric cancer
Curative treatment: up to T1a (N0M0) → endoscopic resection
- En bloc resection using endoscopic mucosal resection (= EMR) or endoscopic submucosal dissection (= ESD)
- Local recurrence (up to T1a) may be resected endoscopically.
- T1b and more (NxM0): surgical resection with curative intent (if operable and resectable)
Radical gastrectomy and D2 lymphadenectomy (operative standard)
- Resection of the lesser and greater omentum and radical lymphadenectomy of compartments I (perigastric lymph nodes along the greater and lesser curvature of the stomach) and II (lymph nodes along the left gastric artery, common hepatic artery, splenic artery, celiac trunk, and along the vessels in hepatoduodenal ligament)
- Splenectomy only in the case of pathological lymph nodes in the splenic hilus and/or a carcinoma of the greater curvature infiltrating the spleen
- Diffuse type (Lauren classification) requires 8 cm proximal safety margin; intestinal type requires 5 cm
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.
- Advantage: The stomach is more protected against bile reflux and consequent complications, such as ventricular ulcer and anastomotic recurrent gastric cancer.
- Extended in the case of cardia carcinoma EGJ Siewert type II and III: abdominothoracic resection of the distal esophagus and cardia, intrathoracic anastomosis by gastric pull-up
- Alternative: subtotal gastrectomy
- No R0 resection: curative reresection aiming at R0, neoadjuvant chemotherapy may complement the treatment
- Indication: distant metastases; advanced tumor stage with unresectable cancer ; functionally inoperable patients
Potential treatment options: Usual palliative measures (e.g., analgesic treatment); in addition chemotherapy, medical management of cancer and/or surgical management may be depending on the patient's general condition
Chemotherapy and medical management of cancer
- Patients with a good ECOG performance status (0-2) may particularly benefit from chemotherapy and medical management, as these measures may prolong life and improve the quality of life.
- Surgical or endoscopic management of gastrointestinal obstruction
- Partial gastrectomies may be used in exceptional cases
- Chemotherapy and medical management of cancer
- 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)
- 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
- Localization: axilla, groin, neck
Malignant acanthosis nigricans always requires further diagnostic measures to look for malignancy!
Related to resorption
- Consequences and management
- Lack of protein and carbohydrates
- Malabsorption of fats leads to fatty stools → Supplement pancreatic enzymes in case of weight loss and inefficient medium-chain triglyceride (MCT) diet.
- Iron deficiency → supplement iron
- Pernicious anemia due to lack of intrinsic factor, usually produced by gastric parietal cells → supplement vitamin B12
- Consequences and management
Related to anastomosis
Small intestinal bacterial overgrowth (SIBO)
- Definition: bacterial overgrowth within the small intestine
- Anatomic abnormalities: (e.g., surgery causing blind intestinal loops – blind loop syndrome ), strictures)
- Motility disorders
- 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
Efferent loop syndrome
- Only an acute abdomen would be an immediate surgical indication, otherwise, watch and wait
- Kinking or anastomotic narrowing of the efferent loop → emesis, feeling of fullness
- Afferent loop syndrome
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.
- 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
- Beta-blockers may be helpful.
- Often spontaneous improvement after a couple of months
- 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
- Prevention: Constructing an esophagojejunostomy with a pouch may prevent dumping syndromes as it creates a useful reservoir. Therefore, this procedure is becoming more common.
- Early dumping
We list the most important complications. The selection is not exhaustive.
- Regular follow-ups after curative treatment are recommended, i.e. every 3–6 months in the first year, and yearly thereafter.
- There are no standard recommendations, but the following approach is often employed:
Patient history and clinical examination
- Identify postoperative dysfunctions, signs, symptoms, and clinical findings indicating local recurrence
- Evaluate nutritional status to prevent weight loss and identify malnutrition and hypovitaminosis at an early stage
- Identify psychosocial stress to patients and relatives → provide support
- Laboratory tests: blood count, iron levels, serum transferrin, transferrin saturation, vitamin B12, tumor marker (if elevated preoperatively or if previous levels are available for comparison)
- Abdominal ultrasound: evidence of recurrence or metasteses
- If recurrence is suspected during follow-up: symptom-oriented restaging
- Patient history and clinical examination
- Following gastrectomy, rehabilitation (ideally in specialized centers) is recommended.
- Specific treatment of usually neglected aspects of the disease:
- Nutrition counseling and training on gastrointestinal dysfunctions following (surgical) treatment
- Identify and treat psychosocial aspects to prevent psychiatric consequences
- Physical therapy and sports (to regain resilience in the management of everyday tasks)
- To ensure appropriate care, geriatric patients may be treated in specific rehabilitation centers.
- 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 (T1, M0, N0, 5-year survival rate 90–95%).
- Distant metastases or peritoneal carcinomatosis dramatically worsen the prognosis and are lethal most of the time.
- 5-year survival rate of stage III is 30%, and of stage IV is 5%.
- Even if the cancer is resectable at UICC-stage II and above, the prognosis is not satisfactory: 5-year survival is less than 50%.