Trends in the survival of patients diagnosed with kidney or urinary bladder cancer in the Nordic countries 1964-2003 followed up to the end of 2006

Abstract

Background: Previous studies have shown systematic differences between the Nordic Countries in population-based relative survival following a kidney or urinary bladder cancer diagnosis. Comparison of bladder cancer over time and between Nordic registries is complicated by variable coding practices with respect to the inclusion of in situ cases with invasive tumours.

Material and methods: Five-year relative survival of patients with urinary cancer diagnosed in the Nordic countries 1964-2003 and followed up for death through 2006 was studied and contrasted with developments in incidence and mortality.

Results: The survival following bladder cancer was higher than for kidney cancer and highest for men. Survival increased over the years in all countries, more for kidney cancer than bladder cancer. For Danish kidney cancer patients, the rate of increase over all the years has been lower than in the other countries, especially among women, resulting in a survival in Denmark some 10-20% points lower than elsewhere in 1999-2003. Danish bladder cancer patient survival was in the last period 4% points lower among men and 10% points lower among women than in the other Nordic countries. The differences were mainly found in the first year following diagnosis, where a higher excess mortality in Denmark was observed. Survival decreased with higher age at diagnosis.

Conclusion: The increasing 5-year relative survival in all the Nordic countries for both kidney and bladder cancer are promising, but for kidney cancer a higher percentage detected coincidentally during an imaging investigation for other diseases could play a role. Denmark had the lowest survival, despite their known practice of including benign conditions with invasive bladder cancers. The lower Danish survival after kidney and bladder cancer in the first year after diagnosis could be due to later diagnosis on average, a higher co-morbidity from smoking-related diseases, and perhaps, less adequate cancer treatment and management in Denmark.