Prostate cancer incidence, mortality and survival trends in Estonia, 1995-2014

The aim of this study was to analyze long-term trends in prostate cancer (PCa) incidence, mortality and survival in Estonia, with specific focus on age and stage.

Data on PCa incident cases and deaths in 1995-2014 were obtained from the Estonian Cancer Registry and the Causes of Death Registry, respectively. Joinpoint regression was used to estimate the annual percentage change for incidence and mortality trends. Relative survival ratios (RSRs) were calculated for four 5 year periods. Incidence and survival were analyzed by age and stage.

The average annual number of new PCa cases in Estonia increased more than three-fold from 1995-1999 to 2010-2014. The age-standardized overall incidence and the incidence of localized cancer increased steeply until 2011, then leveled off. The incidence of locally/regionally spread or distant PCa remained stable. A significant increase in PCa mortality was seen only in men aged 65 years and older. The overall 5 year RSR increased from 58% to 90% over the study period. Survival increased considerably for all stages.

The dramatic rise in the incidence of PCa in Estonia since the late 1990s was limited to localized cancers. This, together with rapid increases in survival, is probably due predominantly to extensive opportunistic prostate-specific antigen testing of middle-aged and elderly men. The ongoing increase in PCa mortality among older men warrants validation of causes of death to avoid possible overestimation. Evaluation of diagnostic and treatment strategies could identify possibilities for improving outcomes of non-localized PCa.