Cancer
Cancer begins with an alteration to the structure of the deoxyribonucleic acid (DNA) that is found in all human cells. This is known as a genetic mutation. The DNA provides the cells with a basic set of instructions, such as when to grow and reproduce.
The mutation in the DNA changes these instructions so that the cells carry on growing. This causes the cells to reproduce in an uncontrollable manner, producing a lump of tissue that is known as a tumour.
How cancer spreads
Most cancers grow and spread to other parts of the body via the lymphatic system. The lymphatic system is a series of glands (or nodes) that are located throughout your body in a similar way to your blood circulation system. The lymph glands produce many of the specialised cells that are needed by your immune system (the body’s natural defence against disease and infection).
Left untreated, oesophageal cancer spreads through the outer lining of the oesophagus and into nearby organs, such as the liver, lungs or stomach.
Risk factors
Exactly what causes oesophageal cancer to develop is uncertain. However, it appears that repeated and prolonged exposure of the lining of the oesophagus to toxic substances is a significant risk factor.
Known risk factors for oesophageal cancer are explained below.
Alcohol
Drinking too much alcohol increases your risk of developing a number of illnesses and conditions, including cancer of the oesophagus. Long-term heavy drinking causes irritation and inflammation in the lining of the oesophagus. If the cells in the lining of your gullet become inflamed, they are more likely to become malignant (cancerous).
Smoking
Using any form of tobacco (including cigarettes, cigars, pipes and chewing tobacco) will increase your risk of developing cancer of the oesophagus.
When you smoke tobacco you always swallow some of the smoke, which contains many harmful toxins and chemicals. These substances irritate the cells that make up the lining of the oesophagus, which increases the likelihood that they will become malignant.
The longer you smoke, the greater your risk of developing oesophageal cancer.
Gastro-oesophageal reflux disease (GORD)
A valve, known as a cardiac sphincter, is located between your stomach and oesophagus. The valve usually only opens when food is ready to pass from your oesophagus into your stomach.
Sometimes, the valve becomes weakened or it relaxes at the wrong time. This condition is known as gastro-oesophageal reflux disease (GORD).
If you have GORD, stomach acid is able to travel up into your oesophagus. When this happens, it causes heartburn, which is a form of indigestion that causes pain in the front of your chest.
However, it should be stressed that the risk of developing oesophageal cancer from GORD is very small, and most people with GORD will not go on to develop cancer.
Barrett’s oesophagus
If you have chronic acid reflux, it can sometimes lead to you developing another condition called Barrett’s oesophagus. Barrett’s oesophagus causes new cells to develop in the lower oesophagus, which are very similar to stomach cells. These abnormal cells are resistant to stomach acid, but they are more likely to become malignant in the future.
Approximately one person out of 10 who have chronic acid reflux goes on to develop Barrett’s oesophagus. You are more at risk if you have had chronic acid reflux for a prolonged period of time. About one person in 100 with Barrett’s oesophagus develops cancer of the oesophagus.
Obesity
If you are severely overweight, your risk of developing cancer of the oesophagus is approximately double, compared with if you were a healthy weight for your height. This may be because obese people are more at risk of developing Barrett’s oesophagus (see above).
Diet
A diet that is low in fruit and vegetables, or lacks vitamins A, C, B1 or zinc has been shown to increase the risk of cancer of the oesophagus. If you eat a healthy, balanced diet, you will usually get enough vitamins and zinc in your diet naturally.
Cancer of the oesophagus is much more common in the Far East and Central Asia. It is thought that this may be due in part to the type of diet that is consumed in these countries, which includes far fewer uncooked vegetables than the western diet. It may also be due to environmental factors.
Ageing
It is very rare for anyone who is under 45 years of age to develop cancer of the oesophagus. Most people who develop the condition are between 55 and 70 years of age. Cancer of the oesophagus is also more common in men than it is in women. For example, in the UK in 2006, 7,824 people were diagnosed with cancer of the oesophagus and 64% (5,034) were male.
Chemicals and pollutants
Long-term exposure to certain chemicals and pollutants may irritate your oesophagus, particularly if you inhale these substances. Chemicals and pollutants that are known to increase the risk of oesophageal cancer include:
- soot
- metal dust
- vehicle exhaust fumes
- lye (a chemical that is found in strong industrial and household cleaners)
- silica dust (which comes from materials such as sandstone, granite and slate)
If you have to work with these substances as part of your job, make sure you take all the necessary health and safety precautions. This should help to minimise your exposure to these potentially harmful substances.
Information and advice about health and safety at work can be found on the Directgov website.
Want to know more?
