Stomach Cancer

Stomach cancer, also known as gastric cancer, happens when cells in the stomach grow in an uncontrolled way and form a tumour. Most stomach cancers begin in the cells that make up the inner lining of the stomach and are a type called adenocarcinoma.

The stomach is part of the digestive system. It receives food from the food pipe (oesophagus), mixes it with digestive juices, and passes it on to the small intestine. A cancer can develop in any part of the stomach, and where it starts can affect the symptoms it causes and the treatment that is recommended.

Stomach cancer tends to develop slowly over many years. Changes in the stomach lining can build up gradually before a cancer forms, which is one reason it is more common in older adults.

Early stomach cancer often causes only mild symptoms that are easy to confuse with common digestive problems. These can include persistent indigestion, heartburn, feeling full quickly when eating, burping, and discomfort or pain in the upper part of the abdomen.

As the cancer grows, symptoms may include loss of appetite, unintentional weight loss, feeling or being sick, tiredness, and difficulty swallowing. Some people notice blood in their vomit, or dark, tar-like stools, which can be a sign of bleeding inside the stomach.

Many of these symptoms are far more often caused by conditions that are not cancer. But because symptoms can be vague, it is important to see a doctor if they are new, persistent, or getting worse, rather than assuming they are nothing serious.

The exact cause is not always known, but several factors are known to increase the risk. Long-term infection with a bacterium called Helicobacter pylori (H. pylori) is one of the most important, because it can cause persistent inflammation of the stomach lining.

Other risk factors include older age, being male, smoking, drinking a lot of alcohol, and a diet high in salted, smoked, pickled or processed foods and low in fresh fruit and vegetables. Long-standing stomach inflammation (gastritis), pernicious anaemia, previous stomach surgery, and a family history of stomach cancer can also raise the risk.

Having one or more risk factors does not mean a person will develop stomach cancer, and some people who develop it have no obvious risk factors. Not smoking, treating H. pylori infection when it is found, and eating a balanced diet may all help lower the risk.

The main test for stomach cancer is a gastroscopy (upper endoscopy), in which a thin, flexible tube with a camera is passed through the mouth to look directly at the lining of the stomach. If an abnormal area is seen, the doctor can take small tissue samples (a biopsy) to be examined under a microscope.

If cancer is confirmed, further tests are used to find out its size and whether it has spread. These can include CT scans, an endoscopic ultrasound, a PET-CT scan, and sometimes a small operation called a laparoscopy to look inside the abdomen. Blood tests may also be done.

This process is called staging. Knowing the stage helps the medical team understand how advanced the cancer is and plan the most suitable treatment.

Treatment depends on where the cancer is, its stage, and a person's general health. A team of specialists works together to recommend a plan, which may use one treatment or a combination of several.

Surgery aims to remove the cancer and is often the main treatment when the disease has not spread widely. This may involve removing part of the stomach (partial gastrectomy) or the whole stomach (total gastrectomy), along with nearby lymph nodes. Very early cancers may sometimes be removed during endoscopy.

Chemotherapy and radiotherapy may be given before surgery to shrink the tumour, after surgery to lower the risk of it coming back, or as the main treatment when surgery is not possible. Some stomach cancers also respond to targeted therapy or immunotherapy, which are matched to specific features of the tumour found through laboratory testing.

Stomach cancer and its treatment can affect eating, digestion and weight. A dietitian can give practical advice, such as eating smaller meals more often, and some people need vitamin or mineral supplements after stomach surgery.

Support is also available for the emotional impact of a cancer diagnosis. Specialist nurses, counsellors and patient support groups can help people and their families cope, and palliative care teams focus on relieving symptoms and improving quality of life at any stage of the illness.

There is no guaranteed way to prevent stomach cancer, but some steps can lower the risk. These include not smoking, keeping alcohol within recommended limits, eating plenty of fresh fruit and vegetables, cutting down on salted and processed foods, and getting treatment for H. pylori infection if it is found.

The outlook depends mainly on the stage at which the cancer is found and on a person's overall health. Cancers found early, before they have spread, are generally easier to treat than those found at a later stage.

Because early symptoms can be vague, getting persistent stomach problems checked promptly is one of the most useful things a person can do. Each situation is different, so the medical team is the best source of information about an individual outlook.