Gastric Adenocarcinoma
Epidemiology & Etiology:
- 2nd most common tumour
in the world (…?)
- Leading cause of cancer death worldwide (…?)
- Decline in incidence and mortality over the
past 6 decades (intestinal type)
- Higher incidence in (intestinal type):
- Japan
- Chili
- Costa Rica
- Columbia
- China
- Portugal
- Russia
- Bulgaria
- Lower incidence in (intestinal type):
- USA
- UK
- Canada
- Australia
- New Zealand
- France
- Sweden
- M:F ~ 2:1 (intestinal type)
- 55y mean (intestinal type)
- Risk factors (intestinal type):
- H.
pylori (HR 5-6)
- Diet:
- Nitrites derived from nitrates (water,
preserved food)
- N-nitroso compounds
- Smoked and salted foods, pickled vegetables,
chili peppers
- Lack of fresh fruits and vegetables
- Green leafy vegetables
- Citrus fruits
- Lack of refrigeration
- benzopyrene
- Low socioeconomic status
- Cigarette smoking (inconclusive)
- Chronic gastritis
- Menetrier
disease
- Partial gastrectomy
- Intestinal metaplasia / gastric adenomas
(precursor lesions)
- Barrett esophagus (GE junction tumours)
- Ethnicity (likely environment rather than
genetic):
- Blacks
- Native Americans
- Hawaiians
- Genetic:
- Blood group A
- Family history (8-10%)
- HNPCC
- Familial gastric carcinoma syndrome
- E-cadherin mutation (CDH1)
- Also increased risk of lobular breast cancer
-
Common sites:
- 50-60% in pylorus and antrum
- 40% lesser curvature
Gross features:
- 3 macroscopic growth patterns:
- Exophytic
- May contain portions of an adenoma
- Flat or depressed
- No obvious tumour
mass in the mucosa
- Linitis plastica – leather bottle consistency
of a portion or entire stomach
- Excavated
- Heaped up, beaded margins
- Shaggy necrotic base
- Overt neoplastic tissue extending into
surrounding mucosa and wall
- Intestinal type:
- Diffuse type:
- Virchow node (left supraclavicular)
- Sister Mary Joseph nodule (subcutaneous
umbilical)
- Widespread peritoneal seeding
Histologic features:
- intestinal type (Laurén
classification):
- glands resembling those of colonic adenocarcinoma
- expanding growth pattern
- often apical mucin vacuoles, abundant mucin in
gland lumens
- gastritis -> atrophy -> intestinal
metaplasia -> dysplasia -> adenocarcinoma
- diffuse type (Laurén
classification):
- gastric-type mucous cells
- scattered individual cells or small clusters
- infiltrative growth pattern
- signet ring cells
- often strong desmoplastic reaction with
scattered malignant
cells within
- intestinal metaplasia is not associated
- WHO classification (based on histologic
appearance)
- Papillary adenocarcinoma
- Tubular adenocarcinoma
- Mucinous adenocarcinoma
- Signet ring cell carcinoma (>50% signet ring
morphology)
- Undifferentiated carcinoma
- Adenosquamous
carcinoma
- Depth of invasion (important in stagining and classification)
- Carcinoma in situ – confined to surface
epithelium
- Early gastric carcinoma is confined to mucosa
and submucosa
- Advanced gastric carcinoma extends into the muscularis propria
- Frequent occurrence of a minor (< 30%)
component of cells with neuroendocrine differentiation
- Should not prevent its classification as
adenocarcinoma
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular features:
- Intestinal type:
- No clear sequence of events
- Mutations:
- Allelic losses
- Microsatellite instability
- E-cadherin expression abnormalities
- c-ERB-B2 amplification
Other features:
- Steady decline in mortality in past 6 decades
- 5 year survival rates remain poor (~20% in the
US)
- Early gastric cancer 90-95% 5-year survival
- Intestinal metaplasia is a precursor lesion
References:
· Kumar V, Fausto N, Abbas A. Robbins & Cotran Pathologic Basis of Disease, Seventh Edition. 7th
ed. Saunders; 2004:1552.
·
Bosman FT, Carneiro
F, Hruban RH, Theise ND
(eds.) WHO Classification of Tumours of the Digestive System (2010)
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Some notes taken
·