Accuracy of Magnetic Resonance Imaging for Local Staging of Prostate Cancer: A Diagnostic Meta-analysis

ContextCorrect assessment of tumour stage is crucial for prostate cancer (PCa) management.ObjectiveTo assess the diagnostic accuracy of magnetic resonance imaging (MRI) for local PCa staging and explore the influence of different imaging protocols.Evidence acquisitionWe searched the PubMed, Embase, and Cochrane databases from 2000 up to August 2014. We included studies that used MRI for detection of extracapsular extension (ECE; T3a), seminal vesicle invasion (SVI; T3b), or overall stage T3 PCa, with prostatectomy as the reference standard. Methodologic quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool by two independent reviewers. Data necessary to complete 2 × 2 tables were obtained, and patient, study, and imaging characteristics were extracted. Accuracy was reported for the most experienced or first reader. Results were pooled and plotted in summary receiver operating characteristics plots.Evidence synthesisA total of 75 studies (9796 patients) could be analysed. Pooled data for ECE (45 studies, 5681 patients), SVI (34 studies, 5677 patients), and overall stage T3 detection (38 studies, 4001 patients) showed sensitivity and specificity of 0.57 (95% confidence interval [CI] 0.49-0.64) and 0.91 (95% CI 0.88-0.93), 0.58 (95% CI 0.47-0.68) and 0.96 (95% CI 0.95-0.97), and 0.61 (95% CI 0.54-0.67) and 0.88 (95% CI 0.85-0.91), respectively. Functional imaging in addition to T2-weighted imaging and use of higher field strengths (3 T) improved sensitivity for ECE and SVI. ECE sensitivity was not improved by endorectal coil use.ConclusionsMRI has high specificity but poor and heterogeneous sensitivity for local PCa staging. An endorectal coil showed no additional benefit for ECE detection, but slightly improved sensitivity for SVI detection. Higher field strengths and the use of functional imaging techniques can slightly improve sensitivity.Patient summaryWe pooled the results from all previous studies that evaluated magnetic resonance imaging (MRI) for detection of tumour growth outside the prostate. MRI is not sensitive enough to find all tumours with extraprostatic growth.