Gleason pattern 4 length and active surveillance eligibility in Grade Group 2–4 prostate cancer

OBJECTIVES: To evaluate whether total Gleason pattern 4 (GP4) length provides better risk stratification than current risk group criteria for determining potential active surveillance (AS) eligibility, using oncological outcomes after radical prostatectomy (RP). PATIENTS AND METHODS: We identified patients with Grade Group (GG) 2-4 disease on magnetic resonance imaging (MRI)-targeted and systematic biopsy who underwent RP. We calculated total GP4 length as the summed millimetres of GP4 in systematic cores plus the average across MRI-targeted cores. Concordance analysis was used to evaluate how increasing GG corresponded to greater GP4 burden. We compared prediction of adverse pathology at RP and 5-year biochemical recurrence (BCR) between risk groups and total length of GP4. RESULTS: Among 2499 patients, 1691, 694, and 114 had GG2, GG3, and GG4 disease, of whom 73%, 19%, and 15% had low amounts (<2 mm) of GP4. Patients with <2 mm of GP4, regardless of GG, had similar risks of adverse pathology (5.2% vs 5.0%) and 5-year BCR (20% vs 21%) as those with favourable intermediate-risk disease; if used as an AS threshold, <2 mm of GP4 would classify approximately twice as many patients as AS eligible, translating to ~50 000 men annually in the United States alone. CONCLUSIONS: Total length of GP4 provides better risk stratification for AS eligibility than current favourable intermediate-risk group criteria. Further defining the optimal method for GP4 quantification and determining the appropriate cut-point is needed before clinical implementation.