Incidence and case distribution according to histological types show large geographical differences [5, 6]. Incidence rates in Northern Europe are higher than in Southern Europe. During the period 1988-1992 Spanish and some Italian Cancer Registries showed the lowest incidence rates [5].

Between 1970 and 1990, the rate of change in mortality has been about 30% to 50% lower in Northern Europe than in the rest of Europe. Greater changes have been detected in Southern European [7]. The recent increase in mortality in Spain is one of the largest in Europe, at around 50% every five years [4].