What is the oesophagus?
The oesophagus (often known as the gullet) is a muscular tube situated behind the trachea (windpipe) in the throat. Food and drink pass from the back of the throat into the stomach through the oesophagus. When food is consumed the muscles at the top of the oesophagus contract, forcing food and fluid downwards into the stomach. At the lower end of the oesophagus there is a muscular valve (the sphincter), which prevents food and fluid being pushed upwards from the stomach. Around 20% to 30% of the population appear to have a weakness of the lower oesophageal sphincter (valve), which allows acidic stomach contents to splash back up into the oesophagus, causing heartburn and regurgitation (reflux), which is the subject of a separate Core leaflet.
Cancer of the oesophagus develops from the lining of the gullet, and has the effect of narrowing the oesophagus and causing difficulty in swallowing. At first solid food tends to lodge or stick in the oesophagus, and this is followed by difficulty in swallowing liquids. The cancerous cells may spread outside the gullet to involve nearby structures, such as lymph nodes and blood vessels in the chest, and may also be carried in the blood stream to form secondary tumours (metastases), in the liver or elsewhere. Most cancers in the upper two-thirds of the oesophagus are known as squamous carcinomas, because they develop from the squamous (skin-like) cells which line the oesophagus. Cancers occurring in the area where the oesophagus joins the stomach are usually adenocarcinomas, derived from stomach-like cells. Adenocarcinoma often develops when the squamous cells at the lower end of the gullet have been replaced by stomach-type (columnar) cells, which have the potential to become malignant. This condition is known as Barrett’s Oesophagus and is mentioned later in this leaflet.
This cancer is particularly common in some parts of Africa and China, and is likely to be partly caused by the local diet or the way that food is preserved and cooked. In Western societies, important risk factors for cancer of the oesophagus include smoking cigarettes and drinking alcohol, particularly spirits. A combination of smoking and spirit-drinking considerably increases the risk. It also appears that the amount of acid reflux (see above) and the period of time over which the oesophagus has been exposed to this acid, are risk factors which may explain the recent increase in the number of cases of adenocarcinoma of the oesophagus. A rare disorder of the muscles of the gullet, known as achalasia, in which there is a failure of relaxation of the muscular valve at the bottom of the gullet, very occasionally leads to cancer.
Oesophageal cancer may cause no symptoms until it begins to obstruct passage of food and fluids down the gullet, or to make swallowing painful (dysphagia). As the cancer develops, there is progressive difficulty in swallowing, at first with solids such as meat and bread, and then with softer foods, and eventually there is difficulty in getting liquids down. Patients begin to lose weight and may have other symptoms, such as choking, coughing, unexplained chest infections or a hoarse voice. Although some patients report long-standing heartburn before developing these symptoms, most people who develop oesophageal cancer have no symptoms of this kind before they experience dysphagia.
How is the diagnosis made?
Most patients seek medical attention because of dysphagia, and going to the doctor early when symptoms begin is important, to increase the chances of early diagnosis and effective treatment. The GP is likely to make a referral to a specialist for investigations. These are likely to include a barium swallow, which involves swallowing a white liquid containing barium, which shows up on X-ray, outlining the oesophagus and revealing any obstruction. Another test likely to be used is an endoscopy, in which a narrow, flexible telescope is passed gently into the gullet through the mouth, using a local anaesthetic throat spray. Changes in the lining of the gullet can be seen and samples taken (biopsy) for laboratory examination. If cancer is diagnosed, other tests may be needed to see if it has spread. These include chest X-ray and ultrasound examinations of the chest, and other tests such as a CT scan or magnetic resonance imaging (MRI) scan. Sometimes it is necessary for a surgeon to look inside the abdomen using a special illuminated tube (laparoscopy).
Surgery is the most commonly used treatment in the United Kingdom, particularly if the cancer has not spread beyond the oesophagus. Depending on the position of the tumour the surgeon may need to enter the chest cavity, the abdomen or the neck, and will remove the affected part of the oesophagus with the surrounding lymph glands. A tube is then made out of the stomach, which is drawn up into the chest or neck where it is joined to the remainder of the oesophagus. Patients are usually cared for in an intensive care ward after this operation and after leaving hospital are able to eat normally, although may feel full rather quickly. This sensation usually improves over the next few months. Sometimes dysphagia (as mentioned earlier in the leaflet) returns weeks or months after the operation. This may be because the cancer has recurred, but often is due to scarring (a ‘stricture’) where the surgeon has made the join. These strictures can be easily stretched using an endoscope. Radiotherapy also offers a potential cure, and it is particularly useful for people with early tumours, especially squamous cancer. Radiotherapy can be used in conjunction with surgery and is also often used as an alternative to surgical treatment, when the type and position of the tumour and the patient’s general condition may influence the decision to operate. When radiotherapy is given in an attempt to cure the cancer it is known as radical radiotherapy or, when the tumour cannot safely be removed by surgery, radiotherapy, sometimes with chemotherapy, is used in smaller doses and is known is palliative radiotherapy, intended to treat the symptoms caused by the cancer. Radiotherapy can be given as an external beam or on the inside of the gullet via an endoscope (brachytherapy).
If surgery is not possible, there are other ways to help to relieve difficulties in swallowing. Endoscopic intubation (or “stenting”) is usually done under sedation or anaesthetic in the endoscopy department. A tube (stent) is inserted into the gullet to keep it open, so that food and fluid can be swallowed without difficulty. These stents are made of either plastic or springy metal coils. They can become blocked by large food particles so that specific instructions on diet are always provided. Sometimes these stents cause troublesome heartburn and regurgitation, which can be helped considerably by taking acid suppressing medication. Endoscopic laser treatment is also possible, and a specialist endoscopist will use a laser to destroy any tumour that is growing into the gullet. In some patients laser treatment and intubation need to be combined.
Major national and international trials are studying the effect of chemotherapy (or combined chemotherapy and radiotherapy), given either before or with surgery, compared to surgical treatment alone. The patient’s specialist will determine exactly which variety of treatment is needed and it will be some time before it is known which patients benefit most from these various treatment methods. A new approach to treatment is the use of photodynamic therapy (PDT), which involves giving the patient a special chemical which enters the cancer cells and is sensitive to certain light wavelengths. When light is passed into the oesophagus using a probe, it activates the chemical which then destroys the cancer. This remains an experimental treatment, currently being investigated in trials.
Patients with Barrett’s Oesophagus (as explained earlier in the leaflet), are at increased risk of developing adenocarcinoma of the oesophagus. To try to prevent cancer developing, these patients are required to undergo endoscopic surveillance (inspection of the oesophagus through an endoscope) every one to two years in an attempt to pick up pre-cancerous changes, known as dysplasia, and prevent progression to cancer. A number of trials of endoscopic surveillance in Barrett’s Oesophagus are still underway, and it is not known for certain how effective different patterns of surveillance are likely to be. Chemoprevention (preventing cancer by using drugs) is an exciting new idea in the prevention of oesophageal cancer, and trials are currently underway to determine whether drugs, such as aspirin giving in conjunction with an acid suppressing agent, are capable of preventing the development of cancer of the oesophagus.
The earliest symptom of cancer of the oesophagus is likely to be difficulty in swallowing food, and prompt consultation with a GP and early investigation are important if a cure is to be achieved. Treatment of cancer of the oesophagus generally involves a surgical operation to remove the affected part of the oesophagus, and this may be combined with radiotherapy or chemotherapy. When a cure is not possible, a number of treatments are available to relieve symptoms. Research is in progress into ways of preventing cancer of the oesophagus, by picking up early pre-cancerous changes or by giving medications which prevent the development of cancer.