Cancers are amongst the commonest causes of death in this country, accounting for about one in every four deaths - almost 130,000 per annum1. The majority of cancer deaths are from tumours found in four principal sites: lung, colorectal, breast and prostate (Figure 1).
Figure 1. Cancer deaths in England and Wales by sex, 1996.
These cancers are common in Western countries but there is a much lower incidence in third world countries (Figure 2). It has been observed that immigrants moving from a low risk area to one of high risk acquire the same risk as the indigenous population within one or two generations suggesting that environmental factors are responsible2.
Figure 2. Geographic variation in the incidence of colon and rectal cancer in men 2.
Tobacco smoking, electromagnetic radiation, environmental chemicals, hormones, bacterial or viral infection, level of physical activity, reproductive and sexual behaviour are thought to be important in the aetiology of cancer at certain sites3. However, it is thought that diet remains the most important factor and it has been estimated that dietary change could result in a reduction of fatal cancers of between 35 and 70%4.
