Survival of prostate cancer patients in central and northern Denmark, 1998-2009

Prostate cancer is the most common noncutaneous cancer among Danish men. During the last decade, use of prostate specific antigen (PSA) testing has increased, and in clinically localized prostate cancer, curative intended treatment has gained a footing. Our aim was to examine possible changes in the short- and long-term survival of patients with prostate cancer during 1998-2009.

From two Danish regions (population, 1.8 million) we included all patients (N = 10,547) with an incident diagnosis of prostate cancer retrieved from the Danish National Registry of Patients. We determined survival after 1, 3, and 5 years, stratified by age, and estimated mortality rate ratios (MRRs) using Cox proportional hazard regression to assess changes over time, controlling for age.

During the study period, the annual number of incident prostate cancer patients more than doubled, and the median age at diagnosis decreased from 74 to 70 years. The survival improved over the study period, particularly in the last half of the period (2004-2009). Thus, 1-year survival increased from 80% (1998-2000) to 90% (2007-2009), corresponding to an age-adjusted MRR of 0.54 (95% confidence interval CI: 0.46-0.63). The expected increase in 3- and 5-year survival was even more pronounced: 47%-73% and 34%-60%, respectively. This corresponded to a 3-year age-adjusted MRR of 0.46 (95% CI: 0.42-0.51) and a 5-year MRR of 0.50 (95% CI: 0.46-0.54). The 1-, 3-, and 5-year overall survival increased in all age groups (<70 years, 70-79 years, ≥80 years).

Survival after prostate cancer has improved in Denmark within the last decade. Although diagnosis and treatment improvements could explain this, length and lead time bias are likely to have influenced our results.