Evidence of overestimating prostate cancer mortality in Estonia: a population-based study

Prostate cancer (PC) mortality statistics in Estonia has shown inconsistencies with incidence and survival trends. The aim of this population-based study was to assess the accuracy of reporting PC as the underlying cause of death and estimate the effect of misattribution in assigning cause of death on PC mortality rates. The Estonian Causes of Death Registry (CoDR) and Cancer Registry provided data on all men in Estonia who died in 2017 and had a mention of PC on any field of the death certificate or had a lifetime diagnosis of PC. A blinded review of medical records was conducted by an expert panel to ascertain whether the underlying cause was PC or other death. We estimated the agreement between the underlying causes of death registered at the CoDR and those ascertained by medical review and calculated corrected mortality rates. The study population included 655 deaths. Among 277 PC deaths registered at CoDR, 164 (59%) were verified by medical review. Among 378 other deaths registered at CoDR, 17 (5%) were ascertained as PC deaths by medical review. In total, the number of PC deaths decreased from 277 to 181 and the corrected age standardized (world) mortality rate decreased from 20 to 13 per 100 000 (1.5-fold overestimation, 95% confidence interval 1.2-1.9). PC mortality statistics in Estonia should be interpreted with caution and possible overestimation considered when making policy decisions. Quality assurance mechanisms should be reinforced in the whole death certification process.