To compare tumor characteristics of screen-detected prostate cancers (PCs) either by digital rectal examination (DRE) or by prostate-specific antigen (PSA) as biopsy indication at low PSA.METHODS.
Two populations with PSA between 2.0 and 3.9 ng/ml were studied. Group-1 was biopsied if DRE was suspicious (1st screening round, N=1877). In group-2 all men were offered biopsy, regardless of DRE result (side-study in 2nd screening-round, N=801). We compared cancer detection rates (CDRs) and tumor characteristics.RESULTS.
In group-1 abnormal DRE prompted biopsy in 253 (13.5%) men (236 (93.3%) actually biopsied). Forty-nine PCs were detected, CDR 49/1877=2.6%. In group-2 we found 120 cancers in 666 (83.1%) men actually biopsied, CDR=120/801=15.0%. Of all cancers detected, organ confinement (clinical T2) was found in 77.5% (group-1) and 96.6% (group-2; of which 99 T1c). Of all PCs 46.9% in group-1 and 15.0% in group-2 had biopsy Gleason score (GS)≥7. In the latter, 15.2% of T1cs were classified GS≥7. Considering only PCs with organ confinement or GS≥7 for each group, CDRs amounted to 2.0% versus 14.5% and 1.2% versus 2.3% for group-1 and group-2, respectively.CONCLUSIONS.
PSA-based screening detected a considerable amount (15.2%) of potentially aggressive tumors as T1cs, but in addition large numbers of possibly insignificant cancers (T1c, GS=6) were diagnosed. DRE seemed to detect more selectively high-grade cancers, but also missed many of these. Considering both populations and the need to detect aggressive but confined cancers, PSA as biopsy indication outperformed DRE at the price of more biopsies (13.5% vs. 100% if all would comply).