INTRODUCTION AND OBJECTIVE:
Accurate Prostate Cancer (PCa) staging is critical in guiding a patient’s treatment decision and it could prevent both under treatment and over treatment. The emergence of focal therapy options has further increased the importance of accurate staging. Patients with pT3b disease (seminal vesical invasion (SVI)) exhibit a poorer prognosis due to increased treatment failure and tumor recurrence. In this study, we investigated the performance of 3T multiparametric Magnetic Resonance Imaging (3TmpMRI) for per-patient detection of SVI in patients with prostate cancer (PCa) with wholemount histopathology (WMHP) reference.
This IRB approved, HIPAA compliant observational study comprised of 647 consecutive men, who underwent 3TmpMRI prior to robotic radical prostatectomy. 3TmpMRI studies were performed with and without an endorectal coil (ERC) in 46.1% (270/586) and 53.9% (316/584) of cases, respectively. 3TmpMRI assessment for probability of SVI was evaluated on a Likert scale (1-5) and cases with score > 2 were considered suspicious for SVI. Per-patient performance of 3TmpMRI for the detection of SVI including sensitivity, specificity, PPV and NPV were evaluated in patients with at least one Region of Interest for PCa on MRI and the clinical (Age and PSA density (PSAD)), imaging (MRI assessment of SVI, ERC, index lesion's PIRADSv2 category, size, level, zone and average ADC) and biopsy (ratio of positive to total cores in systematic biopsy, maximum percentage of the core and highest Gleason Score (low=6 vs high >6)) parameters were compared between patients with and without SVI using bivariate analysis followed by multivariate analysis.
SVI was present on WMHP in 8.9% (52/586) of the patients. Sensitivity, specificity, PPV and NPV were; 30.8% (16/52), 99.3% (530/534), 80% (16/20) and 93.6% (530/566), respectively. On multivariate regression analysis, older age (OR=1.11, p=0.001), PSAD (OR=26.3, p <0.001), 3TmpMRI SVI suspicion (OR=26, p<0.001) and lesion in the peripheral zone (PZ) (OR=16.6, p=0.008) and base (OR=2.4, p=0.023) were significantly associated with presence of SVI. The AUC for the ROC analysis of the final regression model was 0.84.
3TmpMRI has a high specificity, PPV and NPV and fair sensitivity for the detection of SVI. Patients with SVI tend to have older age, higher PSAD and higher likelihood of the index lesion in PZ and base of the prostate.
Source of Funding:
This work was supported by funds from the Integrated Diagnostics Program, Department of Radiological Sciences and Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA