EPIDEMIOLOGY OF ESOPHAGEAL CANCER

Cancer of the oesophagus is the ninth most common cancer in the world, but in developing countries, it is ranked fifth. The epidemiological behaviour of oesophageal cancer is marked by large differences in inci dence within small geographical areas and sharp changes in incidence o ver time which suggest an important role for environmental factors. Th ere is considerable epidemiological evidence indicating that alcohol, tobacco, poor nutrition and thermal injury are responsible for the gre at majority of oesophageal cancers in the Americas, Europe, parts of A frica and Asia and, therefore, control of these factors would lead to a great reduction in the incidence of the disease. Smoking and chewing of opium pyrolysates may be the main cause in high-risk areas of Iran , but the determinants of high risk in China and other populations of the Asian belt remain largely unidentified.