Background Cancer survival is a key measure of the eff ectiveness of health-care systems. Persistent regional and international diff erences in survival represent many avoidable deaths. Diff erences in survival have prompted or guided cancer control strategies. This is the fi rst study in a programme to investigate international survival disparities, with the aim of informing health policy to raise standards and reduce inequalities in survival.
Methods
Data from population-based cancer registries in 12 jurisdictions in six countries were provided for 2•4 million adults diagnosed with primary colorectal, lung, breast (women), or ovarian cancer during 1995-2007, with follow-up to Dec 31, 2007. Data quality control and analyses were done centrally with a common protocol, overseen by external experts. We estimated 1-year and 5-year relative survival, constructing 252 complete life tables to control for background mortality by age, sex, and calendar year. We report age-specifi c and age-standardised relative survival at 1 and 5 years, and 5-year survival conditional on survival to the fi rst anniversary of diagnosis. We also examined incidence and mortality trends during 1985-2005. Findings Relative survival improved during 1995-2007 for all four cancers in all jurisdictions. Survival was persistently higher in Australia, Canada, and Sweden, intermediate in Norway, and lower in Denmark, England, Northern Ireland, and Wales, particularly in the fi rst year after diagnosis and for patients aged 65 years and older. International diff erences narrowed at all ages for breast cancer, from about 9% to 5% at 1 year and from about 14% to 8% at 5 years, but less or not at all for the other cancers. For colorectal cancer, the international range narrowed only for patients aged 65 years and older, by 2-6% at 1 year and by 2-3% at 5 years. Interpretation Up-to-date survival trends show increases but persistent diff erences between countries. Trends in cancer incidence and mortality are broadly consistent with these trends in survival. Data quality and changes in classifi cation are not likely explanations. The patterns are consistent with later diagnosis or diff erences in treatment, particularly in Denmark and the UK, and in patients aged 65 years and older.