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 pams 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 hte 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.
