Abstract
PURPOSE: We assessed whether Prostate Health Index results improve prediction of grade reclassification for men on active surveillance. METHODS AND MATERIALS: 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 (R(1)) vs clinical data+Prostate Health Index (R(3)). We considered an "or"-logic rule combining clinical score and Prostate Health Index (R(4)), and a "2-step" rule using clinical data followed by risk stratification based on Prostate Health Index (R(2)). Rules were applied to a validation set, where values of R(2)-R(4) vs R(1) for specificity and sensitivity were evaluated. RESULTS: 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, R(2) yielded highest specificity at 27% vs 17% for R(1). In the validation set, R(3) had best performance vs R(1) with Δsensitivity = -4% and Δspecificity = +6%. There was slight improvement for R(3) vs R(1) for confirmatory biopsy (AUC 0.745 vs R(1) 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). R(3) did not have better discrimination vs R(1) among the biopsy cohort overall (ΔAUC 0.007, 95% CI -0.007-0.020). CONCLUSIONS: 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.