Aims and background

In 1989, an action plan was adopted by the Nordic Council of Ministers with the aim of reducing cancer mortality in the Nordic countries by 15% around the year 2000. This was to be achieved by removing the causes of cancer, by the early diagnosis of cancer and by improving cancer treatment. The results so far have been disappointing. As the causes of many cancers have been identified over the past 40–50 years, the most efficient way of reducing cancer mortality on the basis of current knowledge would be to reduce the prevalence of exposure of the population to cancer‐causing agents. Such preventive measures take time to implement, however; furthermore, since the process of carcinogenesis entails a lag period that varies from several years to decades, a decrease in cancer mortality will not be immediately evident. We review here the methodological background for estimating the numbers and proportions of cancers in the Nordic countries that could be avoided through primary prevention.