The Oesophagus And Stomach
The oesophagus and stomach are part of the upper gastrointestinal (GI) tract and the digestive system.
The oesophagus is a long tube that delivers food, fluids and saliva from the mouth and throat to the stomach.
The stomach is a hollow, muscular organ in the upper left part of the abdomen, located between the end of the oesophagus and the beginning of the small bowel (small intestine). The stomach stores food that has been swallowed and assists with the absorption of some vitamins and minerals. The stomach also acts to pass the food and water into the rest of the digestive system, including the small and large bowel, where most of the processing of food takes place.
The different layers of tissue (known as the wall) in the oesophagus and stomach are:
Mucosa – the moist innermost layer, which helps move food in the oesophagus. In the stomach it produces fluids that start breaking the food down.
Submucosa – supports the mucosa and gives it blood to survive and take away any of the nutrients.
Muscle layer (muscularis) –pushes food down the oesophagus. In the stomach it helps to mash the food up and assists with pushing the food into the digestive system in a controlled way.
Outer layer (serosa) – surrounds the layers of the stomach. It does not exist around the oesophagus.
In the stomach, acidic (gastric) juices are released from glands in the stomach mucosa. These juices break food down into a thick fluid, which then moves into the small bowel. When the broken-down food is in the small bowel, nutrients from the food are absorbed into the bloodstream. The waste matter moves into the large bowel (large intestine), where fluids are reabsorbed back into the body and the rest is passed out of the body as a bowel movement.
What are stomach and oesophageal cancers?
Oesophageal and stomach cancers are malignant tumours found in the tissues of the oesophagus or stomach. Both cancers start in the mucosa. As they grow deeper into the oesophageal or stomach wall the risk that they might spread to other parts of the body increases.
This cancer can be found anywhere in the oesophagus. In western countries such as Australia this cancer is most commonly found in the lower section of the oesophagus and where the oesophagus meets the stomach (gastro-oesophageal junction).
Oesophageal cancer can occur in different types of cells that exist in the oesophagus. The main types of cancer are:
Squamous cell carcinoma – begins in the cells lining the oesophagus (mucosa), which are called squamous cells. This type of cancer is more common in the middle and upper part of the oesophagus and is more common in Asia, although it is still diagnosed in Australia.
Adenocarcinoma – begins in the glandular tissue of the mucosa, which is found in the lower part of the oesophagus. If oesophageal cancer is not found and treated early, it can grow through the wall into nearby structures. Oesophageal cancers can also spread into the lymphatic system to nearby lymph nodes and through the bloodstream to other parts of the body, most commonly the liver. It can also invade the windpipe, lungs and the lining around the heart.
Most stomach cancers start in the lining (mucosa) in the upper part of the stomach. This type of cancer is called adenocarcinoma of the stomach. Stomach cancer is also known as gastric cancer.
If gastric cancer is not found and treated early, it can grow through the stomach wall into nearby organs such as the pancreas and bowel. Stomach cancer can also spread into the lymphatic system to nearby lymph nodes or through the bloodstream to other parts of the body, such as the lungs. It may also spread to the lining of the abdominal cavity (peritoneum), which can cause swelling in the abdomen.
Rare oesophageal and stomach cancers
There are other less common types of cancer that can affect the oesophagus and stomach, including sarcomas, lymphomas, gastrointestinal stromal tumours (GIST), carcinoid tumours and small cell carcinomas. These types of cancer aren’t discussed here and treatment may differ. Call Cancer Council 13 11 20 for information about these rarer types of cancer, or speak to someone in your medical team.
What are the risk factors?
The exact causes of stomach and oesophageal cancers are unknown, but the following factors may increase your risk. Having one or more of these risk factors does not mean you will develop stomach or oesophageal cancer. See your doctor if you are concerned about your risk factors or any symptoms you are experiencing.
Common risk factors include smoking, high alcohol consumption, and a diet low in fresh fruit and vegetables.
Medical conditions, including gastro-oesophageal reflux disease (GORD) and Barrett’s oesophagus (see below)
A personal or family history of gastro-oesophageal disorders, such as hernia, polyps, ulceration or oesophagitis
Eating smoked, salted, pickled or poorly-refrigerated food
Exposure to certain chemical fumes, fertilisers or dry-cleaning agents
Frequent drinking of very hot liquids.
Infection with Helicobacter pylori (H. pylori), a type of bacteria found in the stomach
Low red blood cell levels (pernicious anaemia)
Chronic inflammation of the stomach (chronic gastritis)
A personal or family history of stomach cancer
Inheriting a genetic change that causes the bowel disorders familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (HNPCC).
GORD and Barrett’s oesophagus
Gastro-oesophageal reflux disease (GORD) and Barrett’s oesophagus are risk factors for oesophageal cancer.
People who have repeated episodes of reflux (heartburn) may be diagnosed with GORD. This is when stomach acid backs up into the oesophagus.
Over time, the walls of the oesophagus become damaged, causing inflammation or loss of tissue (oesophagitis).
In some people this may cause the cells lining the oesophagus to be replaced by a different type of cell. This is called Barrett’s oesophagus.
How common are these cancers?
Over 1300 people are diagnosed with oesophageal cancer in Australia each year. This is an uncommon cancer, making up 1.4% of cancer cases in men and 0.8% of cancer cases in women. However the incidence of adenocarcinoma of the oesophagus in Australia is increasing.
Each year, around 2000 people in Australia are diagnosed with stomach cancer.2 Stomach cancer makes up 2% of cancer cases in men and 1.4% of cancer cases in women.
Both cancers are more common in men – 65% of people diagnosed with oesophegeal cancer and 70% of people diagnosed with stomach cancer are male.
Around 80% of oesophageal and stomach cancers are diagnosed in people aged 60 years and older. The average age that people are diagnosed with cancers of the oesophagus and stomach is around 71.
What are the symptoms of stomach and oesophageal cancers?
In their early stages, oesophageal and stomach cancers may not cause symptoms. These cancers are usually slow-growing and may grow for many years before any symptoms are noticed. This means that they are not usually diagnosed until the cancer is more advanced.
Symptoms of oesophageal and stomach cancers are listed in the box below. These symptoms are common to many other conditions and do not necessarily mean that you have cancer.
However, if you experience any of these symptoms and they are ongoing, make an appointment with your general practitioner (GP).
“A routine check-up with my GP, involving various blood tests, led to gastro-intestinal testing that unearthed early stage oesophageal cancer.” – Julie
Oesophageal cancer symptoms
Pain when swallowing
New or worsening heartburn or reflux
Development of upper abdominal discomfort especially when eating
Black-coloured or bloody stools
Persistent unexplained tiredness
Food or fluids ‘catching’ in the throat or episodes of choking when swallowing
Unexplained weight loss
Stomach cancer symptoms
Pain or burning sensation in the abdomen
Heartburn or reflux
A sense of fullness, even after a small meal
Persistent nausea and/or vomiting with no apparent cause
Unintentional loss of appetite and/or weight
Swelling of the abdomen or feeling bloated
Vomit containing blood
Unexplained tiredness, which may be due to anaemia
Black-coloured or bloody stools