Gastric Tumours

90% Adenocarcinomas
4% lymphomas
3% carcinoids
2% sarcomas

Epidemiology
Western society
2.5 % of cancer mortalities
8/100 000 Males
4/100 000 Females
China and Japan x 5 higher risk

Symptoms
* Insidious and Non-specific
Weight loss
Pain
Anorexia
Vomiting
Altered bowel habit
Anaemia
Haemorrhage

Aetiology
Environmental
Nitrates (smoked/salted/pickled foods)
Absent fruit/veg
Smoking = x1.5-3 Risk
Host
H. Pylori infection (suggested)
Chronic gastritis / Autoimmune atrophic gastritis = x2-4 Risk

Ix
Pylorus/Antrum 50%
Cardia 25%
Body 25%
* lesser curve

Macro
Exophytic (nodular)
Flat (difficult to Dx)
Excavating (mimics PUD - h/e has heaped edge and necrotic centre)
If infiltrates stomach wall = rigid tube k.a. Linitis Plastica

Micro
In-situ - epithelium
Early - submucosa
Advanced - muscular wall

Histology
2 subtypes (Lauren Classification)

1) Intestinal-type Tumours
 - Resemble colonic AdCa
 - Cohesive front
 - *form glandular epithelium with mucin vacoule

2) Diffuse-type Tumours
 - Resemble gastric mucosa
 - Infiltrate as clusters & single cells
 - No glands
 - *signet ring cells

Prognosis
Relevant to depth of tumour invasion
Early Lesions
10-15% of Dx
5yr Survival = 90%
Advanced Lesions
5yr Survival = 15%
Average 5yr Survival = 20%

Invasion: Duodenum/Pancreas/Retroperitoneum
*Spread to supraclavicular nodes (Virchow's Node)