About Gastric Cancer

Author : Bhadresh Bundela

Stomach cancer (gastric cancer)

The vast majority of stomach cancers arise from the glandular lining of the stomach and are called: adenocarcinomas. Some have a finite pre-cancer stage, and it is this stage that the Japanese screening programme is designed to pick up (as this stage is curable by surgery).
Although there are various descriptions that experts have given to the subtyping of the adenocarcinomas of the stomach, there has not overall been a good correlation between histological (i.e. down the microscope descriptions) and outlook for the patient. Molecular biological testing is now helping the pathologist who examines the biopsy to identify some more aggressive characteristics, which will impact on the patient’s outlook. It seems that the over-expression of the c-erb-B2 (HER-2) oncogene by the tumour cells is associated with aggressive tumour behaviour and the over-expression of the EGFR (epidermal growth factor receptor – which is encoded with in the erb-B1 oncogene ) may be related to worse prognosis.
Clearly the prediction of prognosis from molecular testing of the biopsy samples will be a developing area in this disease.

Incidence of stomach cancer (gastric cancer)

Gastric cancer accounts for 6% of cancer deaths in the U.K., where, as in most of the Western world its incidence is decreasing. However, the incidence varies dramatically across the globe and this cancer is the second commonest malignancy in Japan, Latin America and some parts of Northern Europe. For example, in Japan, the disease accounts for 60% of male cancer and 40% of female cancer incidence.
The geographic differences in incidence cannot be simply explained on racial lines/genetic predisposition, as second generation Japanese adopt an incidence that moves toward that of the country in which their parents became domiciled.

Causes of stomach cancer (gastric cancer)

Dietary differences are thought to predispose to gastric cancer: thus, a high intake of complex carbohydrates, nitrates or salt and a low intake of animal fat, protein and salads, fruit and vegetables – all predispose on the available epidemiological evidence. The mechanism of this dietary predisposition is of interest and some speculation: When the acidity of the stomach rises, for whatever reason, bacteria survive which would ordinarily have succumbed due to the low pH. These bacteria chemically reduce nitrates in the diet to nitrites through nitrosation of the dietary amines; these are regarded as carcinogens or co-carcinogens. With regard to protection by fruit and vegetables, it is regarded that ascorbic acid and others may raise the pH and counteract the above process. Advancing age is another predisposing factor; for example, only 2% of cases occur before the age of 30 years of age. The presence of chronic gastritis is another predisposing factor, probably not entirely unrelated to the age factor. The presence of chronic gastritis, par excellence in the disease called pernicious anaemia, is a well recognised predisposing condition for the development of gastric cancer. Stomach infection with Heliobacter pylori is now recognised to be associated with a higher risk of gastric cancer through its causation of a chronic gastritis – the increase in risk in sufferers of this infection for a prolonged time is around six-fold. Once diagnosed the Heliobacter infection is readily eradicated by simple antibiotic therapy. Another infective agent viz. Epstein Barr virus (EBV) has also been linked to a higher incidence of the disease but the link is lees securely established at present.

Screening for stomach cancer (gastric cancer)

The subject of screening is a topical one in Japan, where the incidence of the disease is so high. Here, it has been shown that a diagnosis of early cancer is attended by vastly better survival chances. The screening studies have been by either indirect radiology (barium studies) or endoscopy.

There is no doubt that if the disease is picked up at a very early stage, the patient stands a good chance of cure whereas the majority of patients with advanced disease at presentation succumb from the illness. The problem in the UK is that the disease is sufficiently uncommon, and the required screening test sufficiently uncomfortable and labour intensive that the health economics and the likelihood of population co-operation stack up heavily against he introduction of such a screening programme.

Having said this, there is good reason to refer every patient over forty with dyspepsia, in all its formats, for screening endoscopy/gastroscopy.

Symptoms of stomach cancer (gastric cancer)

Most patients present to the doctor with ‘dyspepsia’ – a term that means so many things to different people that it needs some expansion: the majority of patients will not feel satisfaction when eating and many some upper abdominal discomfort or pain. Others will find fullness or discomfort such as leads their appetite to suffer. Others will find themselves full after a small amount of food or that the have lost the desire to eat. Weight loss ensues.

If the patient presents late then discomfort due to enlargement of the liver – due to spread of the cancer to this organ – may occur or jaundice due to liver dysfunction, for the same reason. This is clearly the most dangerous presentation.