Magnetic Resonance or Computed Tomography and Bone Scan for Staging Metastatic Hormone-Sensitive Prostate Cancer.

Background: Computed tomography with bone scans (CT-B) has been widely used for staging metastatic hormone-sensitive prostate cancer (mHSPC), but whole-body magnetic resonance imaging (WB-MRI) is increasingly adopted. This study compares WB-MRI and CT-B in detecting metastatic sites, disease classification (CHAARTED and LATITUDE), and treatment outcomes in mHSPC.

Methods: This retrospective study included patients with mHSPC diagnosed between February 2017 and August 2023 at 2 UK NHS hospitals. Patients underwent baseline staging with either WB-MRI or CT-B. Data on demographics, disease extent, and treatment were analysed. Patients were stratified using CHAARTED and LATITUDE criteria. Survival outcomes were assessed using Kaplan-Meier and Cox regression analyses.

Results: Among 203 patients (120 WB-MRI, 83 CT-B), WB-MRI identified higher rates of bone-only disease (47% vs 22%, P < .001), high-volume (49% vs 22%, P < .001), high-risk (47% vs 18%, P < .001), and de novo metastatic disease (91% vs 65%, P < .001), but lower lymph node-only metastases (10% vs 26%, P = .003) and prior radical treatment (surgery: 2% vs 13%, P < .001; radiotherapy: 7% vs 25%, P < .001). CHAARTED (HR 4.922, 95% CI: 1.937-12.507, P < .0001) and LATITUDE (HR 4.807, 95% CI: 1.674-13.809, P = .003) classifications independently predicted overall survival, with significant volume/risk differences only observed in WB-MRI (P < .001 and P = .001, respectively).

Conclusions: Whole-body magnetic resonance imaging appears to enhance staging accuracy and risk stratification in mHSPC, potentially influencing treatment decisions. While limited by retrospective design, these findings suggest that WB-MRI may optimise management in mHSPC, warranting further prospective validation.