Features and preliminary results of prostate cancer screening in Canton Aargau, Switzerland

To report the results from Switzerland's participation in the ERSPC from 1998; importantly, epidemiological data showed that Switzerland has one of the highest rates of morbidity and mortality from prostate cancer in the world. The local study protocol was accepted by the ethical committee and after the successful pilot study phase, the centre joined the ERSPC.

From September 1998 to June 2003 10 300 men accepted an invitation for the study and were then randomized 1:1 into an active screening arm (assessed by testing prostate-specific antigen, PSA) or a control group (no intervention). The re-screening interval is 4 years and is ongoing (beginning in September 2002). The study protocol includes offering a prostate biopsy when the total PSA is >3.0 ng/mL (the main study protocol in agreement with ERSPC requirements) or when the total PSA is 1-3 ng/mL and the free-to-total PSA ratio <20% (side study protocol).

During the first 3 years of screening 3562 men aged 55-70 years were screened; 395 (11.1%) of all participants had a total PSA of >3 ng/mL and 251 (7.4%) were eligible for the side-study. In all, 599 (17.2%) of 3562 accepted a prostate biopsy (93% of 646); 120 cases of prostate cancer were detected (3.4% detection rate). The incidence was 2.5% in main study group (positive predictive value, PPV, 24%) and 0.9% in side study group (PPV 13.6%). In radical prostatectomy specimens the cancers were mostly 'significant' (92% in main study group and 87% in side-study group).

A randomized screening study for prostate cancer is feasible in Switzerland. A longer follow-up is needed to address within the ERSPC the primary hypothesis (that there will be a reduction in mortality in the active screening arm) and to determine the level of over/under-diagnosis and over/undertreatment in the active screening and control arms, respectively.