In males, gastric carcinoma is one of the most common causes of death from gastrointestinal malignancies, second only to colorectal and pancreatic cancer.
It is more common in Asian countries like Japan and also has a higher incidence amongst males above the age of 50.
Gastric cancer may be classified according to its cell type. 95% of all gastric cancer are adenocarcinomas (tumour of glandular tissue of epithelial origin), of which can be further subdivided into either intestinal type (which carries a better prognosis) or of diffuse type (worse prognosis).
The rarer types include lymphoma (Stomach is the most common site for GI Lymphoma), neuroendocrine (carcinoid) and smooth muscle (leimyosarcoma).
The image below demonstrates poor to moderately differentiated adenocarcinoma of the stomach.
Staging is a more useful indicator for prognosis than cell type. Staging is the assessment of Tumour extent, Nodal status and presence of Metastasis - TNM. Combinations of TNM make up the UICC stage. e.g. T1 N0 M0 is UICC stage 1. The 5-year survival at this stage is 70% but plunges to 30% when UICC is stage 2 (T2 N0 M0).
The image below illustrates the assessment of Tumour extent. Table below shows the different TNM stages.
Way of spread
The most common mode of spreading in adenocarcinoma is local spread (i.e. to adjacent organs like the pancreas). Another method is via the blood (haematogenous spread) , through the portal vein to the liver.
Lymphatic spread is usually a late feature (local nodal involvement to distant nodal metastasis such as Virchow's node in the left supraclavicular fossa) and carries a poor prognosis. Likewise for transcoelomic spread where the tumour passes through the peritoneal cavity to surround structures like the ovaries (Kruckenberg tumour).
Several risk factors for developing gastric carcinoma have been identified. Modifiable risk factors include smoking, alcohol and a diet rich in nitrosamine (a common preservative).
Non-modifiable risk factors include a positive family history for gastric cancer and being blood group A.
Chronic gastritis is a common risk factor and the pathology behind it is metaplasia to intestinal cell resulting to dysplasia and carcinoma. It can come as a result of pernicious anaemia / peptic ulcers / untreated H. pylori infection.
Signs and Symptoms
As with many malignancies, the signs and symptoms of gastric carcinoma include weight loss, nausea and anorexia.
Dyspepsia is a common complaint. Unfortunately, the increasing popularity of PPIs (proton pump inhibitors) in this group of patients without investigation can delay diagnosis.
As malignancies tend to ulcerate, this may casuse melaena and iron deficiency anaemia. However, it may also present in a dramatic fashion of upper GI bleed.
Depending on where the lesion is located, particularly in the stomach outlet (pylorus), patient may also present with symptoms of gastric content outflow obstruction (e.g. early satiety and vomiting).
Distant metastasis can cause ascites, hepatomegaly and cervical lymphadenopathy.
Examination may be completely normal. However, comment on whether the patient is cachexic or jaundiced on general examination.
Before examining the abdomen, examine the hands (look out for signs of iron deficiency anaemia - pallor, koilonychia), neck (lymphadenopathy – Virchow's node), face and eyes (conjunctival jaundice). Then examine the abdomen: inspect for any obvious abdominal masses, palpate for tenderness and percuss for ascities.
For bloods, a full blood count may indicate iron deficiency anaemia whilst liver function tests may indicate metastasis (e.g. elevated bilirubin for metastasis to liver or elevated ALP for metastasis to bone).
A barium meal (see image below - showing gastric carcinoma in the greater curvature) can help to identify a mass where it is large. However, endoscopy and biopsy is more diagnostic and an urgent endoscopy is warranted in patients who are aged 55 or present or presents with signs and symptoms of the above.
CT scan will help stage the cancer (e.g. Nodal status).
In UICC stages 1-3, radical resection of the stomach is a method of treatment which involves partial/total gastrectomy and regional lymph nodes. A Roux-en-Y procedure aka "Gastric bypass" (see image below) may be employed to anastamose the distal oesophagus to jejunum.
In UICC stage 4, palliative management is usually the only option, involving radiotherapy, chemotherapy and surgery. Where surgery is undertaken, its aim is to alleviate symptoms of dysphagia, cachexia and vomiting.
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