A multicenter, retrospective case-control study by the iTNM Consortium demonstrated that magnetic resonance imaging (MRI)-based T staging had similar discrimination to traditional digital rectal examination (DRE)-based clinical staging for biochemical recurrence, distant metastasis, and overall survival among patients undergoing radical prostatectomy for prostate cancer. The findings were published by Peyrottes et al in JAMA Network Open.
“This study’s results suggest that MRI-derived staging may replace DRE staging without compromising accuracy, supporting its integration into contemporary risk models in the modern prostate cancer diagnostic pathway,” the investigators commented.
Study Details
The analysis included 4,425 men (median age = 66 years) with clinically localized or locally advanced prostate cancer who underwent radical prostatectomy, preoperative multiparametric MRI, and systematic biopsies, with or without targeted biopsies, at 31 referral centers across six European countries between 2015 and 2021. Patients who had received prior prostate cancer treatment or had missing key variables were excluded.
The investigators created MRI-based versions of established preoperative risk stratification systems (D’Amico, European Association of Urology, National Comprehensive Cancer Network, and International Staging Collaboration for Prostate Cancer) by replacing DRE-derived T stage (cT) with MRI-derived T stage (iT), and compared their performance with the original DRE-based systems.
Follow-up data were provided for a median of 52 months. The investigators identified distant metastasis–free survival as the primary outcome. Biochemical recurrence–free survival and overall survival were evaluated as secondary outcomes. Discriminatory performance was assessed using the concordance index (C-index) and time-dependent area under the receiver operating characteristic curve analysis.
Key Findings
Compared with DRE-based staging, MRI-based staging showed slightly improved discriminatory performance for biochemical recurrence–free survival (MRI: C-index = 0.62, 95% confidence interval [CI] = 0.61–0.64; vs DRE: C-index = 0.59, 95% CI = 0.57–0.61) and distant metastasis–free survival (MRI: C-index = 0.67, 95% CI = 0.64–0.70; vs DRE: C-index = 0.65, 95% CI = 0.62–0.68).
However, the investigators observed comparable discrimination between the MRI- and DRE-based versions of the four risk classification systems, as reflected by overlapping 95% CIs. No significant differences in time-dependent area under the receiver operating characteristic curves were observed between MRI- and DRE-based staging throughout follow-up.
Similar results were observed in subgroup analyses of patients with cT1 disease and those with prostate-specific antigen levels under 10 ng/mL.
“In this case-control study of patients with localized prostate cancer treated with radical prostatectomy, MRI-based staging demonstrated performance similar to traditional DRE-based staging for biochemical recurrence, distant metastasis, and overall survival,” the investigators concluded. “These findings suggested that MRI-derived staging could be integrated into contemporary risk classification systems without compromising accuracy.”
They added, “Future prospective studies and incorporation of radiomic or genomic data may further clarify the oncologic risk estimation value of MRI-based staging.”
Arthur Peyrottes, MD, MSc, of Hôpital Saint-Louis, Assistance Publique–Hôpitaux de Paris, Université Paris Cité, is the corresponding author of the article in JAMA Network Open.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
