ABSTRACT
In Chapter 1, colorectal cancer has been identified as a worldwide major medical problem in ‘westernized’ countries (Figure 2.1).1 For some decades, the USA, which is a highincidence area, has recognized its public health importance. There, the incidence has recently shown a slight downturn, possibly because of the changes in lifestyle and dietary habits that have also reduced the incidence of cardiovascular disease. Mortality has also declined, mainly in US White women, and this reflects both its earlier diagnosis and improved therapy (see Figure 1.2 in Chapter 1). This high incidence is also found in those ethnically diverse and non-‘Western’ countries such as Japan, Singapore, and Israel, as well as the Czech Republic, etc., and occurs
within one or two generations in immigrants moving from countries with a low colorectal cancer incidence to host countries of high incidence. From this, epidemiologists quickly concluded that acquired environmental and lifestyle factors must be the major etiological causes.2
