Oesophageal cancer (also called cancer of the oesophagus) is a malignant tumour that grows in the lining of the oesophagus. The oesophagus (the gullet) is the tube that carries food from the mouth down into the stomach using a series of muscular movements.

Types of oesophageal cancer
Two types of cancer, squamous cell carcinoma and adenocarcinoma, make up 90 per cent of all oesophageal cancers. Oesophageal cancer can occur in any section of the oesophagus. Most cancers in the top part of the oesophagus are squamous cell cancers. They are called this because the cells lining the top part of the oesophagus are squamous cells. Squamous means scaly.

Most cancers at the end of the oesophagus that joins the stomach are adenocarcinomas. Adenocarcinomas are often found in people who have a condition called Barrett's oesophagus. In Barrett's oesophagus, long term gastro-oesophageal reflux damages the normal squamous cells that line the oesophagus by repeatedly bathing them in acidic stomach contents. Over time the squamous cells are replaced by cells more like the ones in the stomach, which are columnar cells that secrete mucus and are resistant to acid. It is in these new cells, the so-called Barrett's metaplasia, that adenocarcinomas often develop. Because 5-10 per cent of people with Barrett's oesophagus will go on to develop cancer of the oesophagus, they are regularly screened to detect any pre-cancerous cells that may develop.

Who gets oesophageal cancer?
Oesophageal cancer is relatively uncommon in Australia but in some parts of Asia it is very common. In many Western countries adenocarcinoma is becoming much more common.

What causes oesophageal cancer?
What causes this type of cancer is not fully understood, but it is thought that there are a number of risk factors and conditions that, if present for any length of time, may lead to oesophageal cancer. These include the following.

•  Achalasia: a condition where the muscles of the lower oesophageal sphincter (the ‘valve' that controls food passing from the oesophagus to the stomach) can't relax properly and so food builds up in the oesophagus and doesn't pass to the stomach. Also, the normal waves of muscle contractions that propel food down the oesophagus don't work properly, also adding to the build-up of food.

•  Barrett's oesophagus: a condition caused by repeated episodes of reflux that results in acid-resistant cells, like the ones in the stomach, growing in the oesophagus and replacing the usual cell lining of the oesophagus.

•  Damage to the oesophagus by the swallowing of caustic agents.

People who smoke or drink large quantities of alcohol on a regular basis are thought to be at higher risk for this type of cancer. Other risk factors include:

•  eating nitrites or toxins from fungi.

You should always check with your doctor if you have any difficulty swallowing or have constant episodes of reflux, or if you develop any of the symptoms that may indicate oesophageal cancer. Early detection of this cancer is extremely important as it does improve the chance of successful treatment. Unfortunately, this type of cancer, even if successfully treated, can often recur even after surgery, chemotherapy and/or radiation treatment.