Adherence to a risk‐adapted screening strategy for prostate cancer: First results of the PROBASE trial

PROBASE is a population‐based, randomized trial of 46 495 German men recruited at age 45 to compare effects of risk‐adapted prostate cancer (PCa) screening starting either immediately at age 45, or at a deferred age of 50 years. Based on prostate‐specific antigen (PSA) levels, men are classified into risk groups with different screening intervals: low‐risk (3 ng/ml, recommendation for immediate biopsy). Over the first 6 years of study participation, attendance rates to scheduled screening visits varied from 70.5% to 79.4%, depending on the study arm and risk group allocation, in addition 11.2% to 25.4% of men reported self‐initiated PSA tests outside the PROBASE protocol. 38.5% of participants had a history of digital rectal examination or PSA testing prior to recruitment to PROBASE, frequently associated with family history of PCa. These men showed higher rates (33% to 57%, depending on subgroups) of self‐initiated PSA testing in‐between PROBASE screening rounds. In the high‐risk groups (both arms), the biopsy acceptance rate was 64% overall, but was higher among men with screening PSA ≥4 ng/ml (>71%) and with PIRADS ≥3 findings upon multiparameter magnetic resonance imaging (mpMRI) (>72%), compared with men with PSA ≥3 to 4 ng/ml (57%) or PIRADS score ≤ 2 (59%). Overall, PROBASE shows good acceptance of a risk‐adapted PCa screening strategy in Germany. Implementation of such a strategy should be accompanied by a well‐structured communication, to explain not only the benefits but also the harms of PSA screening. What's new? Screening for prostate‐specific antigen (PSA) reduces deaths from prostate cancer, but routine PSA screening for all participants leads to overdiagnosis and overtreatment. The PROBASE study, initiated in 2014, uses a risk‐adapted PSA screening strategy that adjusts the screening schedule depending on the participant's initial PSA level. Here, the authors report that adherence rates during the first 6 years of the trial were good, with attendance rates in the 70% to 80% range, and the biopsy acceptance rate was 71% among men with PSA of 4 or higher.