Assessment of causes of death in a prostate cancer screening trial

Abstract

Accurate assessment of the causes of death is crucial for a conclusive evaluation of the ongoing prostate cancer screening trials. Here, we report the validity of the official causes of death as compared with an independent expert review in the Finnish prostate cancer screening trial. Because nearly 80,000 men were involved, death-cause evaluation was restricted to men diagnosed for prostate cancer. Medical charts were retrieved and the cause of death was assigned by an expert review panel for all deaths among men with prostate cancer during the study period, 1996-2003. The panel decision was compared with both death certificates and the official causes of death as assigned by Statistics Finland. Of a total of 315 deaths, the review panel attributed 127 (41%) to prostate cancer and 184 (59%) to other causes, the corresponding figures in death certificates being 124 (40%) and 187 (60%). Four cases were excluded because of insufficient information. The death-certificate data were in agreement with the panel's assessment in 305 out of 311 cases (overall agreement 97.7%, kappa = 0.95). The overall agreement between the official causes of death and the panel's decision was 97.4% (304/311, kappa = 0.95). The sensitivity of the certificates in identifying prostate cancer deaths was 96.1% (panel as golden standard). Correspondingly, specificity was 98.9%. The official causes of death thus provide an accurate means for evaluating disease-specific mortality in a large population-based prostate-cancer screening trial in Finland.