The stomach is a J shaped hollow organ in the upper abdomen that receives food as it passes from the oesophagus (gullet). Digestion of food begins in the stomach before it passes to the intestines. In addition the stomach performs a number of other important functions including being involved in the absorption on vitamin B12, which is important for making red blood cells. The most common form of stomach cancer is adenocarcinoma. Less common malignant tumours of the stomach are lymphomas and gastro-intestinal stromal tumours (GIST).
Gastric cancer is the second most common malignancy world wide. However it is much less common in Australia compared with other cancers such as lung cancer, breast cancer and melanoma. Gastric cancer is responsible for 1873 cancer deaths in Australia and can affect approximately 1 in 153 people to the age of 75. It is more common with increasing age and effects men twice as common as women.
The best understood risk factor for gastric cancer is infection with the Helicobacter pylori bacterium which can chronically inflame the inside of the stomach lining, leading potentially to cancerous changes. Infection of this bacteria can also lead to stomach lymphoma. Dietary factors have been associated with increase risk of gastric cancer which included things such as smoked fish and possibly high consumption of red meat, smoking and alcohol abuse. A diet high in fruits and vegetables can potentially decrease stomach cancer risk. Stomach cancer is also associated with previous stomach surgery such as the removal of stomach tissue for peptic ulcer disease, benishis anaemia, stomach polyps and a strong family history of stomach cancer. The symptoms of gastric cancer are very vague and hence the majority of patients present with quite advanced disease. Symptoms may include indigestion, upper abdominal pain, a bloated feeling after eating and a sensation of getting full quickly, nausea, loss of appetite and heartburn. More advanced stages can be associated with vomiting and blood in the vomit, unexplained weight loss and paradoxically distension of the abdomen. These symptoms may be associated with a large number of benign ulcers. However if they are present for any length of time one should consult a Doctor.
Unlike colon cancer there is no widely used screening program in Australia for stomach cancer because it is relatively uncommon. However if you have symptoms that your Doctor suspects, means that you may have stomach cancer they should firstly arrange for you to have an examination of the inside of your gullet and stomach by endoscopy. This involves using a flexible lighted tube that is inserted into the mouth usually with sedation. There is a camera at the end of the telescope that enables your Doctor to see inside the stomach as well as permits the taking of small samples of tissue to examine for cancer. At times it may be necessary also to undergo a barium X-ray of the stomach and intestines. Once the diagnosis of gastric cancer is made on biopsy a number of other investigations are required to fully stage (that is to determine the extent of the tumour and whether it has spread to any other organs). Staging for stomach cancer will usually take the form of a CAT scan of the chest, abdomen and pelvis. I may also involve another staging technique called laparoscopy. This involves minor surgery with a general anaesthetic. It essentially involves a keyhole operation where a camera is placed inside the abdomen through one small hole using another small hole to examine the abdomen for the presence of any stomach cancer spread beyond the stomach. Finally a newer technique called endoscopic ultrasound may also be used. This is similar to a gastroscopy which has an ultrasound probe on the end of the gastroscope that is passed into the stomach. This allows very accurate local staging of the tumour with respect to it’s spread into the wall of the stomach and it’s relationship to near by organs and lymph nodes.
The choice of treatment for stomach cancer depends on the stage of the disease. Specifically that relates to the size of the tumour in the stomach and how deeply it is spread through the wall of the stomach, whether it is spread to involve lymph nodes and whether it has spread to other parts of the body. The main stay of any curative treatment for a patient with stomach cancer involves complete removal of the tumour and the associated lymph nodes. This is performed if the staging studies indicate that surgery is likely to help and the tumour has not spread beyond the stomach and the lymph nodes. The operation to remove the tumour involves removing either some (approximately three quarters) of the stomach called a subtotal gastectomy or all of the stomach known as a total gastrectomy. In a total gastrectomy this involves removal of the entire stomach and the small intestine is joined directly to the oesophagus. During the surgery the surgeon will also remove lymph nodes to examine them for cancer cells. At times it may also be necessary to remove the spleen and also part of the pancreas. See what is in consent forms from PA
While surgery is the main stay of curative treatment the results still need to be better for many patients with stomach cancer. As a result a number of treatment options have been explored in attempts to improve outcomes for patients with stomach cancer. The best evidence supports two different approaches at this time. The first approach involves chemotherapy over approximately an eight week period of time with a subsequent four week rest period before undergoing surgery. Then once the surgery has taken place, approximately six weeks later a further three cycles of chemotherapy over eight weeks in total once again are administered. This has been shown to improve survival in a large trial conducted in the United Kingdom. The alternative approach is to undergo surgery initially and receive chemotherapy and radiation therapy in the post operative period. These options will be discussed in more detail and treatment tailored to the individual patient based on their stage and general level of fitness. In addition a newer treatment is beginning in the form of a clinical trial in Australia through the AGITG (Australian Gastrointestinal Trials Group). For patients who have stage IV disease (that is stomach cancer that has spread beyond the stomach and lymph nodes to involve other organs) treatment is not curative and usually take the form of chemotherapy for patients who are fit and may involve radiation for control of specific symptoms.