PURPOSE: To assess differences in treatment between the screening and control arm of European Randomized study of Screening for Prostate Cancer (ERSPC) Rotterdam and to study if possible treatment differences explained the positive study outcome.
MATERIALS AND METHODS: In ERSPC Rotterdam, men aged 55-74 were randomized between a screening (n=21210) and a control arm (n=21166). Treatment after diagnosis was left to the care provider of the patients choice. Initial treatment was compared within four risk groups. The relation between prostate cancer incidence and prostate cancer mortality was assessed per risk group by correlating the relative risk (RR) of prostate cancer incidence and the RR of prostate cancer mortality. A direct relation would support a stage shift as the main cause of changes in prostate cancer mortality.
RESULTS: Initial treatment differed between the arms in the low-, intermediate-, and high-risk groups, but not in the metastatic group. RR of prostate cancer incidence and prostate cancer mortality per risk group were 1:1 related (slope of regression line 1.00, 95% confidence interval (CI); 0.30-1.74) and 94% of the changes in prostate cancer mortality could be explained by changes in prostate cancer incidence. This makes differences in treatment unlikely as the reason for the observed prostate cancer mortality reduction.
CONCLUSION: Differences in treatment between the screening and control arm of ERSPC Rotterdam were unlikely to explain the differences in prostate cancer mortality. Instead results are consistent with a reduction in prostate cancer mortality as a result of a favourable stage through screening.
Bokhorst LP, Venderbos LD, Schröder FH, Bangma CH, Steyerberg EW, Roobol MJ. Are you the author?
Department of urology, Erasmus University Medical Centre, Rotterdam, the Netherlands; Department of public health, Erasmus University Medical Centre, Rotterdam, The Netherlands.
Reference: J Urol. 2015 Feb 16. pii: S0022-5347(15)00295-5.