Lesion Volume Dynamics Add Prognostic Value Beyond Prostate Imaging Reporting and Data System Score Increase for Predicting Confirmatory Biopsy Upgrade During Active Surveillance
Purpose: This study aimed to evaluate the association of Prostate Imaging Reporting and Data System (PIRADS) score increase and lesion volume progression on serial prostate magnetic resonance imaging (MRI) with confirmatory biopsy outcomes in a racially and ethnically diverse cohort of patients undergoing active surveillance for prostate cancer.Materials and Methods: We conducted a single-center retrospective cohort study of men with Gleason 3+3 and 3+4 prostate cancer managed with active surveillance at our institution from 2016 to 2025 who had diagnostic and confirmatory biopsies and corresponding prostate MRI examinations within prespecified windows of each biopsy. Biopsy-level, demographic, clinical, imaging, and treatment data were abstracted. Imaging progression was defined as any increase in maximum PI-RADS score or a ≥30% increase in maximum lesion volume (MLV). Outcomes included Gleason grade group (GG) upgrading and increased length of Gleason pattern 4 (GP4) on confirmatory biopsy. Multivariable logistic regression models adjusted for age, race/ethnicity, time between biopsies, prostate-specific antigen density, and GG at diagnosis were used to evaluate associations between imaging progression and upgrading. Receiver operating characteristic analysis was used to compare discriminative performance.Results: Among 160 patients (73% Black or Hispanic/Latino), 52 (32.5%) had upgrading at confirmatory biopsy. In separate multivariable models, both PI-RADS score increase (odds ratio [OR], 4.06; 95% confidence interval [CI], 1.77–9.76; p=0.001) and MLV increase ≥30% (OR, 4.29; 95% CI, 1.98–9.74; p<0.001) were independently associated with upgrading on confirmatory biopsy compared with no interval imaging change. On receiver operating characteristic analysis, MLV increase (area under the curve [AUC], 0.673) and combined PI-RADS score and MLV progression (AUC, 0.714) outperformed PI-RADS score increase alone (AUC, 0.619). Among patients with baseline GG2 disease, PI-RADS score increase was associated with increased GP4 burden from diagnostic-to-confirmatory biopsy.Conclusion: During early active surveillance, progression in MRI-derived tumor volume provided clinically meaningful prognostic information beyond PI-RADS score increase for predicting upgrading on confirmatory biopsy, including in a racially and ethnically diverse cohort. Incorporating MRI change metrics may help guide decision-making about confirmatory biopsy in active surveillance protocols.