Objectives: To assess the value of dynamic contrast-enhanced magnetic resonance imaging (MRI) for the prediction of extracapsular extension (ECE) in patients with clinical T3 (cT3) prostate cancer (PCa) compared to digital rectal examination (DRE).
Materials and methods: A retrospective review of data for patients treated by radical prostatectomy for cT3 PCa was performed. Patients who underwent MRI in the pre-operative work-up were included. The likelihoods of extracapsular extension (T3a) and seminal vesicle invasion (T3b) were scored on the basis of MR images. For data analysis, receiver operating characteristic (ROC) curves were generated.
Results: Overall, 70 consecutive patients were included. Mean age was 63.8 (range 45-75) years, and the mean PSA level was 11.3 (range 2.9-26) ng/ml. Pathological analysis of the prostatic specimens confirmed 81.4% (n = 57) had pT3 disease. According to MRI, 57 (81.4%) patients were predicted correctly to have T3 disease. The overstaging (actual pT2) by either DRE or MRI or both was 18.6, 7 or 7%, respectively. The sensitivity, specificity and positive (PPV) and negative predictive values (NPV) of MRI were 94.7, 69, 93 and 75%. The kappa index of concordance between pre-operative MRI stage and pathological stage was 0.68 (P < 0.00001). The performance of MRI for T3 staging was AUC 0.87 (95% CI, 0.77-0.97).
Conclusions: Pre-prostatectomy MRI adds significant incremental value to the assessment of patients with cT3 disease. Its ability to accurately predict and characterize pathological T3 status and its superiority to standard clinical variables (e.g. DRE) confirm its usefulness in pre-operative work-up.