Gastric Cancer
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Introduction
10-12/100,000 in North America
70-80/100,000 in East Asia
Gastric maltomas (mucosal-associated lymphatic tissues) are antigen-induced lymphomas following chronic inflammation.
Gastrointestinal stromal tumours (GIST) original in the interstitial cells of Cajal (pacemaker cells of the gut). Almost all are associated with gain of functon in KIT genes.
The Case of...
Causes and Risk Factors
Increasing age is a significant risk factor. Males have a 2:1 risk.
More cancers at the GE junction:
Nutritional
- low fat or protein consumption
- salted meats or fish
- high nitrate
- high complex-carrbohydrate consumption
Environmental
- lack of refrigeration
- smoking
medical
- prior surgery
- H pylori
- gastric atrophy and gastritis and pernicious anemia
- adenomatous polyps
familial
- HNPCC
- FAP
- BRCA2
- CDH1
Pathophysiology
Development
Hyperplastic gastric polyps are found in 2-3% of endoscopies; almost half are fundic.
They do NOT gise to cancer
Colorectal neoplasia can be found in over half of patients with benign gastric polyps, while gastric adenocarcinoma develops in 2%
Adenomatous polyps account for 10% of polyps. They are most often antral and suggest increased risk of cancer development.
Cancers tend to not track further than the pylorus.
Staging
T3: through serosa without invading adjacent structures
Cancer is most likely along the lesser curve.
Cancer along the great curve is more likely to spread to nodes ajoining the spleen.
Intestinal
- environmental risk factors
- gastric atrophy and intestinal metaplasia and gland formation
- men > women
- increasing incidence with age
- hematogenous spread
- microsatellite instability
- APC gene mutations
- p53, p16 inactivation
Diffuse (Leather bottle)
- blood type A
- women > men
- younger age group
- poorly differentiated, signet ring cells
- transmurallymphatic spread
- decreased E-cadherin
- p53, p16 inactivation
Signs and Symptoms
- history
- physical exam
History
Loss of appetite
- difficulty swallowing
- vague abdominal fullness, particularly following meals and increasing over time
- nausea and vomiting
- vomiting/passing blood
- abdominal pain
- excessive belching
- breath odor
- excessive gas (flatus)
- unintentional weight loss (poor predictor)
- general decline in health
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
Endoscopy is the best means of identifying cancer
CT scan and laparoscopy can be helpful for pre-operative staging. Laparoscopy, along with peritonal lavage, can be helpful for diagnosing peritoneal
Differential Diagnosis
peptic ulcer
Treatments
Surgery
A distal cancer is resected, with generous margins extending but part of the body left intact to be attached to the duodenum. A more proximal cancer will result in total gastrectomy, with the esophagus becoming attached to the
Chemotherapy
GIST is treated very successfully with Gleevec, or imatinib.
Consequences and Course
Resources and References
Topic Development
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