The first serious efforts to estimate the number of new and existing cancer cases in a given population were made at the turn of the century in various European countries. In Germany, an attempt was made in 1900 to register all cancer patients who were under medical treatment. Questionnaires were sent to every physician in the country to record the prevalence of cancer on 15 October 1900 (Anon., 1901). The same approach was adopted between 1902 and 1908 in Denmark, Hungary, Iceland, the Netherlands, Portugal, Spain and Sweden. These efforts were not very successful, however, mainly due to poor collaboration by the physicians. Similar surveys were conducted in.
