Prostate cancer specific mortality in the Florence screening pilot study cohort 1992-1993

The impact of screening on prostate cancer mortality is still unknown. A favourable impact is suggested by uncontrolled and possibly biased studies. Mortality from all causes and from prostate cancer was assessed in a cohort of 6861 males aged 60-74 years, participants to a pilot screening study during 1991-1994. Observed/expected mortality was determined by linkage with cancer and mortality registries. Prostate cancer standardised mortality rate (SMR) in the overall series (751 subjects excluded by GPs for disabling illness or prostate cancer; 3448 refusers, 2662 attenders; 67,321.2 men-year) was 0.96 (95% confidence interval (CI) = 0.74-1.22) when deaths from prevalent cancers diagnosed before screening were considered. Reduced prostate cancer mortality (SMR = 0.48; 95% CI = 0.26-0.83), persisting beyond five years after study entry (SMR = 0.48; 95% CI = 0.22-0.90), was observed in attenders and not in refusers (SMR = 0.99; 95% CI = 0.69-1.37). This finding might suggest a screening effect, but might also be ascribed to an healthy screening effect, and cannot be assumed as a reliable evidence of screening efficacy.