Gastric Cancer

Gastric cancer

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Gastric Cancer by Mind Map: Gastric Cancer

1. Common findings

1.1. Abdominal pain- epigastric, vague, mild in early stage, becomes severe in late stage

1.2. weight loss

1.3. dysphagia common when tumor located in proximal stomach

1.4. indigestion

1.5. early satiety

1.6. nausea

1.7. vomiting

1.8. feeling bloated after eating

2. Diagostic tests

2.1. upper gastrointestinal endoscopy with biopsy

2.2. barium studies: false negatives can occur in 50% of cases, preferred method to detect linitus plastica (an aggressive form of diffuse type of gastric cancer

2.3. abdominal CT scan to look for metastasis

2.4. endoscopic ultrasound to assess tumor depth and lymph nodes

2.5. staging laprascopy- to directly visualize the liver surface, peritoneum, & local lymph nodes, allows detection of metastasis more precisely

2.6. Serologic markers

2.6.1. elevated alpha-fetoprotein

2.6.2. there are 5 circulating micro RNAs that have been found to upregulated in gastric cancer

2.6.3. serum pepsinogen is a marker of mucosal atrophy and inflammation

2.6.4. serum antigens

3. Risk factors

3.1. Heliobacter pylori infection

3.2. diet high in salted, smoked foods

3.3. male gender

3.4. smoking

3.5. older age

3.6. intake of process meats like sausage, bacon, ham, and beef jerky

3.7. obesity

3.8. occupational exposures: coal/tin mining, metal processing, rubber manufacturing

3.9. chronic gastritis

3.10. Epstein Barr virus

3.11. Type A blood

3.12. family history

4. Causative factors

4.1. Infection

4.1.1. Heliobacter pylori

4.1.1.1. Over 95% of gastric cancers develop due to H. pylori infection but only a minority of infected individuals develop gastric cancer

4.1.1.2. Half of the world's population is infected with this bacterium

4.1.1.3. Differences in gastric cancer development may be due to virulence of H. pylori and host factors

4.1.1.4. H. pylori strains that produce cytotoxin-assoicated gene A (CagA) protein are highly virulent with severe outcomes

4.1.1.5. In Asian countries, almost all strains of H. pylori posess CagA which may even exist after H. pylori eradication

4.1.1.6. detected by blood tests, urine (not as specific), urea breath test, and stool antigen

4.1.1.7. classified as definite carcinogen in 1994

4.1.2. In Western countries, less than 10% of cancers are due to infections. In Japan, approximately 25% of cancers are infection related

4.2. Inflammation

4.2.1. Chronic gastritis

4.2.2. results in epitheleal cell damage with increased free radical generation

5. Treatments

5.1. Surgery

5.1.1. subtotal gastrectomy

5.1.2. total gastrectomy

5.1.3. splenectomy

5.1.4. lymph node removal

5.2. chemotherapy

5.3. radiation therapy

5.4. targeted therapy

5.4.1. monoclonal antibody therapy: uses antibodies made in lab from a specific immune cell, is used to kill cancer cells

5.4.1.1. given by infusion

5.4.1.2. trastuzumab: blocks effects of growth factor protein HER2

5.4.1.3. ramucirumab: blocks effects of VEGF

5.5. Immunotherapy: uses patient's immune system to fight cancer, pembrolizumab is a type of immune checkpoint inhibitor

6. Pathophysiologic etiology

6.1. Gastritis with infiltration of neutrophils or lymphocytes develops within a few months in nearly 100% of people infected with H. pylori

6.2. persistent inflammation increases the fragility of the gastric mucosa and progresses to atrophic gastritis: this can take 10-20 years

6.3. After atrophic gastritis develops, the annual incidence of cancer is 0.1 to 0.4% in Japanese patients

6.4. In early gastric cancer, infiltration of tumor cells is limited to mucosa and submucosa, most curable at this time but seldom detected in U.S. due to lack of symptoms and screening

6.5. H. pylori infection almost constantly induces a specific immune response which is followed by antibody production

6.6. Adenocarcinoma histology accounts for 90-95% of all gastric malignancies

6.7. exact etiology is unknown

7. Incidence & Prognosis

7.1. In 2019 there were 27,510 new cases and 11,140 deaths

7.2. In U.S. gastric cancer ranks 14th in incidence of major cancers

7.3. Rates of gastric cancer have been declining worldwide over the last 50 years probably due to refrigeration which reduces the need to preserve foods by salting and smoking

7.4. Most patients diagnosed in the U.S. are symptomatic and have advanced, uncurable disease

7.5. Screening is not widely performed in U.S. Usually screening done in countries with high incidence (Japan, Venezuela, & Chile

7.6. 5th most common cancer worldwide and 3rd leading cause of cancer deaths worldwide

7.7. In U.S. and Europe, 5-year survival is only 10-25%

7.8. In Japan, 5-year survival of early cancer is over 90% (they have early detection)

7.9. In Japan, gastric cancer accounts for 17% of all cancers. Incidence in Western countries is low