Effect of MRI and site variation on surgical treatment for prostate cancer.
BACKGROUND Increased utilization of prostate magnetic resonance imaging (MRI) over the past decade may have led to a system shift in the patient population selected for radical prostatectomy (RP). We evaluated whether the initial use of MRI before biopsy resulted in the selection of lower-risk patients for RP. MATERIALS AND METHODS We evaluated patients undergoing RP in the Veterans Health Administration from 2014 to 2024. We compared patients receiving MRI-informed initial biopsy to those who had initial biopsy without MRI. For the primary analysis, multivariable mixed-effects ordinal regression evaluated whether prebiopsy MRI utilization was associated with stage or grade at RP. We secondarily evaluated rates of upgrading/downgrading at RP and rates of treatment for Grade Group (GG) 1 disease. RESULTS Adjusting for CaP risk factors, Veterans Health Administration site, and year of treatment, MRI-informed initial biopsy was associated with higher pathologic T stage (OR 1.12, 95% CI 1.01-1.26, P = 0.048) and GG (OR 1.13, 95% CI 1.02-1.25, P = 0.015) at RP. We observed no difference in downgrading between groups (difference: -0.8%, 95% CI -0.9% to 2.5%, P = 0.4). However, patients with MRI-informed initial biopsy had slightly lower rates of upgrading (difference: -4.2%, 95% CI, -5.6% to -2.8%, P < 0.001). The median frequency of GG1 on RP was 2.6% (IQR 1.4%-4.5%) and varied significantly by site (P < 0.001). CONCLUSIONS MRI utilization prior to biopsy was overall associated with higher T stage and grade at the time of prostatectomy. Overall decreased rates of upgrading at RP, however, may reflect greater biopsy concordance with use of MRI or the selection of higher-risk patients for multimodal or systemic therapies.