Aetiology of Oesophageal Cancer in Africa - A Review of Historical and Current Evidence

There is no current agreement on the cause of squamous cancer of the oesophagus in Africa, a major cause of morbidity and mortality in East and Southern Africa. The remarkable history is reviewed together with all recent evidence using a literature search. There are consistent and continuing associations with maize and with tobacco. Changes of type of maize, patterns of consumption and processing occurred around 1930, and a rapid rise of oesophageal cancer dated from that time. Tobacco has a worldwide association with cancer of the oesophagus, but there is a substantial minority of non-users in high incidence areas. Other carcinogens have come under suspicion, but there is evidence against any of these acting as the principal carcinogenic influence in Africa. Recent studies in Japan and in South Africa have shown an association between non-acid gastro-oesophageal reflux and squamous cancer of the oesophagus. There is no credible candidate for principal oesophageal carcinogen in Africa. There is good reason to look again at milled maize- its deficiencies, contaminations, and degenerative processes. Associations between diet, non-acid reflux and squamous cancer of the oesophagus merit further study.