Summary
The oesophagus is the muscular tube that connects the bottom of the neck with the stomach, carrying food though the chest. The muscles in the tube push lumps of chewed food downward. The cells lining the oesophagus are mainly squamous cells, which are flat. However, the cells in the bottom part of the oesophagus can change into ones that are similar to those found in the stomach if, over time, acid reflux/ heartburn has been present.
There are therefore two main types of oesophageal cancer: Squamous Cell Cancer and Adenocarcinoma.
Causes
The two main types of oesophageal cancer have both separate and overlapping causes.
Squamous Cell Cancer of the Oesophagus
Smoking and Drinking are the main risk factors for this disease
Eating foods that contain certain nitrogen chemicals, such as pickled vegetables, increases the risk of oesophageal cancer (as does Betel nut chewing). An increase in the incidence has been seen in regions where tea is drunk at very hot temperatures.
It is thought that Zinc may be protective.
Individuals who have a disease called ‘achalasia’, where the muscles of the oesophagus do not move well, are at increased risk, as are those who have chemically caused narrowing’s. Tylosis is another disease that has a raised risk of developing squamous cell oesophageal cancer; it causes a darkening of the palms and soles and is an inherited condition.
Adenocarcinoma of the Oesophagus
It is thought that virtually every case of adenocarcinoma of the oesophagus arises from an area of the lining of the oesophagus that has undergone a change. This change happens because acid, formed in the stomach has been washing over the lining for a long time. This process turns the cells lining the oesophageal lumen into ones that resemble those found in the stomach. These changes are called Barrett’s oesophagus. Patients with this may have had heartburn for a long time, but as many as 40% of people with Barrett’s oesophagus have not had any symptoms.
Barrett’s oesophagus is a premalignant condition detected in the majority of patients with oesophageal or gastro-oesophageal adenocarcinoma – cancers that, once established, have a low survival rate (perhaps 5-15% five year survival).
Barrett’s oesophagus is diagnosed in approximately 15% of patients undergoing oesophagoscopy for for reflux/oesophagitis symptoms and is an important condition because of its premalignant status. The progression from low grade dysplasia Barrett’s to high grade (as detected by a biopsy of the affected area at the bottom of the oesophagus) is a sinister development with a higher risk of imminent frank malignant change.
Smoking may increase the risk of oesophageal adenocarcinoma, but the association is not as strong as with squamous cell carcinoma.
Obesity is a definite risk factor, probably because it increases the risk of Barrett’s Oesophagus, described above.
Incidence
Oesophageal cancer is becoming more common. In 2004 there were 6600 cases in the UK, accounting for 3% and 2%of all cancers in men and women respectively. It is the adenocarcinomas that tend to occur in the looser part of the oesophagus that is increasing in incidence.
Symptoms & diagnosis: Oesophageal cancer
The first symptom is usually difficulty in swallowing, first to very solid, dry foods, but then progressing to less solid food. There may be a sensation of the food sticking that goes away with drinking fluids to force the food past an obstruction. Weight loss and a reduced appetite are also possible.
Chest pain is possible, and sometimes coughing immediately after swallowing can occur if an abnormal connection between the swallowing tube and the breathing tube (trachea) has been made by the tumour.
Diagnosis
If a patient has difficulty swallowing the first investigation that is done is usually an X ray taken whilst swallowing a liquid that shows up on X ray pictures. This is called a Barium Swallow. It shows up narrowing’s in the oesophagus and areas where the lining is irregular. If there is an abnormality, the next usual test is an endoscopy.
This uses a flexible camera that is passed through the mouth in to the throat and then down the oesophagus. The procedure is done under sedation, i.e. the patient is given a medicine to make them sleepy to reduce the discomfort of the procedure.
The endoscopy allows the doctor to look directly at the oesophagus and to take a sample (a biopsy) of any abnormal areas.
These samples are examined under the microscope to look for cancer cells. The type of the cancer can also be determined.
Stages
The ‘stage’ of any cancer is a description of its size, local spread and distant spread. Defining the stage is crucial in deciding the most appropriate treatment and whether it is possible to aim to cure the disease. Scans are the most important method of working out the stage of the disease.
Oncologist will use internationally recognised systems of staging, but the principles are to decide the following:
The main concern whether the growth is confined to the oesophagus or whether it has spread to other organs.
Where the disease is localised then it may be possible to aim for a cure, otherwise palliation is the best approach.