Introduction: The EUROCARE II study

This introduction provides a general overview of the aims, methods and proc edures used in the EUROCARE II study and the types of analyses presented in each article of this Special Issue of the European Journal of Cancer. The main aims of the EUROCARE II project are the updating of the survival datab ase of the European Cancer Registries, the study of recent trends in relati ve survival rates and the interpretation of the survival differences observ ed both in time and across populations. Once having completed the prelimina ry stage of data checking, a total of 3 473 659 individual records from pat ients of all cancer sites, diagnosed between 1978 and 1989 and provided by 45 cancer registries in 17 European countries were accepted to build up the EUROCARE database. The quality of these data, in terms of the accuracy of the diagnosis and the validity of vital status assessment, was checked by i ndirect indicators, based on cross-validation analysis of consistency of th e relevant variables. Statistical analysis was based on age-specific relati ve survival rates, computed for each cancer sites as the ratio of observed survival to the expected survival of the general population of the same are a, gender and age, according to the Hakulinen method. An estimate of the Eu ropean survival was computed as a weighted mean of the corresponding surviv al of the different countries, using as weights the expected yearly number of incident cases in each country. For comparison purposes, age-standardise d survival was also calculated for Europe and for each country involved in the study. (C) 1998 Elsevier Science Ltd. All rights reserved.