Impact of Prostate Health Index Results for Prediction of Biopsy Grade Reclassification During Active Surveillance

We assessed whether Prostate Health Index results improve prediction of grade reclassification for men on active surveillance.

We identified men in Canary Prostate Active Surveillance Study with Grade Group 1 cancer. Outcome was grade reclassification to Grade Group 2+ cancer. We considered decision rules to maximize specificity with sensitivity set at 95%. We derived rules based on clinical data (R₁) vs clinical data+Prostate Health Index (R₃). We considered an "or"-logic rule combining clinical score and Prostate Health Index (R₄), and a "2-step" rule using clinical data followed by risk stratification based on Prostate Health Index (R₂). Rules were applied to a validation set, where values of R₂-R₄ vs R₁ for specificity and sensitivity were evaluated.

We included 1,532 biopsies (n = 610 discovery; n = 922 validation) among 1,142 men. Grade reclassification was seen in 27% of biopsies (23% discovery, 29% validation). Among the discovery set, at 95% sensitivity, R₂ yielded highest specificity at 27% vs 17% for R₁. In the validation set, R₃ had best performance vs R₁ with Δsensitivity = -4% and Δspecificity = +6%. There was slight improvement for R₃ vs R₁ for confirmatory biopsy (AUC 0.745 vs R₁ 0.724, ΔAUC 0.021, 95% CI 0.002-0.041) but not for subsequent biopsies (ΔAUC -0.012, 95% CI -0.031-0.006). R₃ did not have better discrimination vs R₁ among the biopsy cohort overall (ΔAUC 0.007, 95% CI -0.007-0.020).

Among active surveillance patients, using Prostate Health Index with clinical data modestly improved prediction of grade reclassification on confirmatory biopsy and did not improve prediction on subsequent biopsies.