Summary
Unless otherwise stated, the article below refers to gastric adenocarcinoma
Epidemiology
- The second most common cancer worldwide (behind lung cancer)
- Most common in South America and Japan (due to diet)
- 8th most common cancer in the UK
- Male:female is 2:1
Aetiology
- Nitrates in the diet
- H pylori infection
- Smoking
- Atrophy of stomach tissue (e.g. after resection, also occurs in 1% of H pylori infections)
- Genetic factors
Symptoms
These are usually similar to that of ulcers
- Dyspepsia
- Weight loss
- Anorexia (loss of appetite)
- Vomiting / nausea
- Feeling of fullness/bloatedness
- Anaemia (iron-deficiency)
- Mass
- Virchow’s node
Pathology
Almost always an adenocarcinoma of the mucous secreting cells of gastric pits. The most common mutation is that of tumour suppressor gene p53. Some tumours may ulcerate.
Investigations
- Endoscopy
- USS
- CT – for disease staging
Staging is done using the
TNM scale
Treatment
This is basically resection of the stomach. However, tumours usually present too late to be operated on. The 5 year survival in the UK is about 10%. Surgery can also leave you with serious side effects.
Oesophageal carcinoma
This almost always occurs in the presence of Barrett’s oesophagus, and is basically just an adenocarcinoma of the new columnar epithelium – i.e. it is like gastric carcinoma, but just in the oesophagus.
Likely to present with dysphagia
This accounts for 1-2% of gastric carcinomas.
H pylori is again a large precipitating factor
Unless otherwise stated, the article below refers to gastric adenocarcinoma
Epidemiology
- Very common in Chine, South America, Scandinavia and Japan – because the diets of people in these regions tend to be high in nitrates. Less common in Britain, and not very common in the USA. The USA has similarly low rates in people of Chinese / Japanese ethnicity, and therefore we can deduce that environmental factors are very important.
- It is the second most common malignancy worldwide (behind lung cancer).
- There is evidence to show that gastric carcinoma is correlated to infection rates with H. Pylori.
- M:F 2:1, and incidence rises sharply after the age of 50.
- It is the 8th most common cancer in the UK, and has an incidence of 12-15 per 100,000. Incidence around the world is falling.
- It is very rare in people under 30.
- Japan has an extremely good screening system (because the disease is so common there), and it has 5 year survival rates of about 80%. In the rest of the developed world, the 5 year survival rate is about 10%. This is because usually the cancer is asymptomatic in the early stages, and by the time it presents it has developed too far.
- The average age of presentation is 50 to 70.
Aetiology
- Diet (smoked fish, pickled foods, salt, nitrates) Foods known to have a beneficial effect are fresh fruit and vegetables, particularly those containing vitamin C and A.
- H. Pylori – it is thought that this is responsible for 60-70% of cases. You are at greater risk if you get the infection if you are young, and if you are one of the people who goes hypochlorohydric when they get it (~1% of people who are infected). H. Pylori will often cause inflammation, leading to gastritis, leading to gastric atrophy, which can lead to gastric carcinoma.
- Smoking
- Gastric polyps
- FAP (familial adenomatous polyposis)
- Genetic factors – e.g. HDC-1 mutations
- Resection of the stomach (e.g. form an old peptic ulcer – they don’t really use this treatment any more) is also a disposing factor. This is because resecting the stomach will ultimately reduce gastric acid secretion, which will lead to gastric atrophy, and gastric atrophy is a predisposing factor for gastric cancer.
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