Abstract
Conditional relative survival (CRS) and competing mortality are important survivorship issues after cancer treatment. We aimed to investigate them among patients with prostate cancer treated by various modalities.
Using a nationwide population-based database, we calculated 5-year CRS conditioned on 1 through 5 years survival after diagnosis. These rates were stratified by age, sex, socioeconomic status, comorbidities, and treatment received. Cause of death and estimated cause-specific mortality were also described and considered with competing risks.
A total of 81,773 patients newly diagnosed with primary prostate cancer from 2007 to 2013 were identified. The 5-year CRS was 81.1% at baseline, but increased gradually up to 95.4% at 4 years and exceeded 100% at 5 years after diagnosis, suggesting no excess mortality compared with the general population. However, this pattern differed by treatment received. Patients who underwent androgen deprivation therapy showed 5-year CRS of only 88.4% at 5 years after diagnosis, implying persistent excess mortality. Prostate cancer constituted around one-third of deaths, while other cancers were the main cause of death within <2 years after diagnosis. Noncancer-related deaths, including cardiovascular disease and respiratory disease, increased with time since diagnosis.
CRS rates for patients with prostate cancer improved over time and exceeded that of the general population at 5 years. Other cancers were the main cause of death in the earlier survivorship phase, and deaths from noncancer causes gradually increased over time.
Our findings will help patients and clinicians make evidence-based decisions on the basis of a patient's dynamic risk profile.
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