Do We Need Early Detection of Grade Group 2 Prostate Cancer in a Screening Program for Young Men? Results from the PROBASE Screening Trial.

In general, low-risk and favorable intermediate-risk prostate cancers (PCs; International Society of Urological Pathology grade group [GG] 1 and GG 2) are slow-growing cancers with low metastatic potential. Active surveillance is recommended for GG 1 PC and can be recommended for GG 2 PC in the absence of adverse pathological parameters. Therefore, the question arises as to when low-grade PC should be detected in a screening setting. We conducted an analysis of the group with intermediate prostate-specific antigen (PSA) risk (1.5-2.99 ng/ml) from the PROBASE screening trial for young men (starting age 45 yr) and evaluated 159 biopsies performed for confirmed PSA ≥3 ng/ml in the first two biennial screening rounds. Of these biopsies, 37% were positive, with 78% (46/59) showing GG 1 or GG 2 disease. Only 0.8% of men with intermediate risk (13 of 1661 men screened) had GG 3-5 PC and would have experienced a delay in diagnosis of between 1 and 3 yr if screening were performed at 5-yr intervals. These results suggest that the screening interval could be extended from 2 yr to 5 yr for men aged 45 yr at intermediate risk, similar to the interval for men at low risk (PSA <1.5 ng/ml). This would reduce unnecessary testing and overdiagnosis in nearly 10% of the screening population aged 45 yr.