Projected Outcomes of Reduced-Biopsy Management of Grade Group 1 Prostate Cancer: Implications for Relabeling.

Abstract

Implications of relabeling grade group (GG) 1 prostate cancer as non-cancer will depend on the recommended active surveillance (AS) strategy. Whether relabeling should prompt de-intensifying, PSA-based active monitoring approaches is unclear. We investigated outcomes of biopsy-based AS strategies vs PSA-based active monitoring for GG1 diagnoses under different patient adherence rates. We analyzed longitudinal PSA levels and time to GG ≥ 2 reclassification among 850 patients diagnosed with GG1 disease from the Canary Prostate Active Surveillance Study (2008-2013). We then simulated 20,000 patients over 12 years, comparing GG ≥ 2 detection under biennial biopsy against three PSA-based strategies:(1) PSA: biopsy for PSA change ≥20%/year, (2) PSA+MRI: MRI for PSA change ≥20%/year and biopsy for PI-RADS ≥3, and (3) Predicted risk: biopsy for predicted upgrading risk ≥10%. Under biennial biopsies and 20% dropout to active treatment, 17% of patients had a > 2-year delay in GG ≥ 2 detection. The PSA strategy reduced biopsies by 39% but delayed detection in 32% of patients. The PSA+MRI strategy cut biopsies by 52%, with a 34% delay. The predicted risk strategy reduced biopsies by 31%, with only an 8% delay. These findings are robust to biopsy sensitivity and confirmatory biopsy. PSA-based active monitoring could substantially reduce biopsy frequency; however, a precision strategy based on an individual upgrading risk is most likely to minimize delays in disease progression detection. This strategy may be preferred if AS is deintensified under relabeling, provided patient adherence remains unaffected.