Stability of Prognostic Estimation Using the CAPRA Score Incorporating Imaging-Based vs Physical Exam-Based Staging.

PURPOSE: Although official T-staging criteria for prostate cancer center on digital rectal examination (DRE) findings, providers increasingly rely on transrectal ultrasonography (TRUS) and magnetic resonance imaging (MRI) to define pragmatic clinical stage to guide management. We assessed the impact of incorporating imaging findings into T-staging on performance of a well-validated prognostic instrument.

MATERIALS AND METHODS: Patients who underwent radical prostatectomy for prostate cancer diagnosed between 2000-2019 with stage ≤cT3a on both DRE and imaging (TRUS/MRI) were included. The UCSF-CAPRA score was computed 2 ways: (1) incorporating DRE-based T-stage and (2) incorporating imaging-based T-stage. We assessed for risk changes across the 2 methods and associations of CAPRA (by both methods) with biochemical recurrence (BCR), using unadjusted and adjusted Cox proportional hazards models. Model discrimination and net benefit were assessed with time-dependent area under the curve (AUC) and decision curve analysis, respectively.

RESULTS: Of 2222 men included, 377 (17%) increased in CAPRA score with imaging-based staging ( P < .01). DRE-based (HR 1.54; 95% CI 1.48-1.61) and imaging-based (HR 1.52; 95% CI 1.46-1.58) CAPRA scores were comparably accurate for predicting recurrence with similar discrimination and decision curve analyses. On multivariable Cox regression, positive DRE at diagnosis (HR 1.29; 95% CI 1.09-1.53) and imaging-based clinical T3/4 disease (HR 1.72; 95% CI 1.43-2.07) were independently associated with BCR.

CONCLUSION: The CAPRA score remains accurate whether determined using imaging-based staging or DRE-based staging, with relatively minor discrepancies and similar associations with BCR. Staging information from either modality can be used in the CAPRA score calculation and still reliably predict risk of BCR.