Mortality Risk for Patients with Biopsy Gleason Grade Group 1 Prostate Cancer.

Background and objective: We investigated the association of clinical factors at presentation with the presence of unsampled high-risk prostate cancer (PC) and PC-specific mortality (PCSM) and all-cause mortality (ACM) following radical prostatectomy in patients with biopsy Gleason Grade Group (GGG) 1 PC.

Methods: The study population comprised 10228 patients treated for GGG1 PC diagnosed via transrectal ultrasound (TRUS)-guided systematic biopsy (SBx; n = 9248) or combined biopsy (CBx; SBx + TRUS/magnetic resonance image [MRI] fusion biopsy; n = 980) from a cohort study at a university hospital in Hamburg, Germany. We used logistic, Fine and Grays, and Cox multivariable regression methods to calculate the adjusted odds ratio (aOR) of adverse pathology and adjusted hazard ratios (aHRs) for early prostate-specific antigen (PSA) failure (≤18 mo), PCSM, and ACM in relation to each clinical factor.

Key findings and limitations: Irrespective of biopsy approach, percent positive biopsies (PPB) >50% and PSA >20 ng/ml were significantly associated with higher risk of adverse pathology (SBx: aOR 1.71 and 3.49; CBx: aOR 1.81 and 2.82, respectively) and early PSA failure (SBx: aHR 1.54 and 4.37; CBx: aHR 2.88 and 7.81, respectively). PPB >50% and PSA >20 ng/ml were also associated with higher risk of PCSM (aHRs 2.56 and 3.71) and ACM (aHRs 1.47 and 2.00) in the SBx group (all p ≤ 0.04). The study is limited by the single-institution cohort design.

Conclusion and clinical implication: Maintaining the "cancer" classification for patients with GGG1 and either PPB >50% or PSA>20 ng/ml and considering rebiopsy to identify unsampled high-grade disease may minimize the risk of mortality for this subgroup.

Patient summary: For patients undergoing non-targeted prostate biopsy, approximately 1 in 12 with a biopsy result of grade group 1 prostate cancer may have more aggressive cancer than the result suggests. A very high PSA (prostate-specific antigen) level (>20 ng/ml) or the presence of grade group 1 cancer in more than 50% of the biopsy samples can identify patients at risk.