Tumor suspicion on MRI incorporating T 2 and Diffusion-weighted imaging predicts adverse pathology on radical prostatectomy

Objective: The objective of this study was to determine whether suspicion for tumor on pretreatment prostate magnetic resonance imaging (MRI) incorporating T2 and diffusion-weighted imaging (DWI) predicts more adverse pathology following radical prostatectomy (RP) in prostate cancer patients. Methods: A single-institutional retrospective analysis was performed on 745 patients who underwent 3.0 Tesla pelvic-phased-array MRI of the prostate that included T2 and DWI before RP between July 2009 and December 2015. Patients were grouped into no suspicion for tumor (NST), equivocal suspicion for tumor (EST), or strong suspicion for tumor (SST) based on MRI findings. Preoperative variables and post-operative pathology, including primary Gleason score (≥ 4 vs < 3), pathological stage (≥ pT3 vs < T3), surgical margin and lymph node positivity, were compared between the three groups. A univariate logistic regression analysis was used to assess the associations between preoperative parameters and surgical pathology. Multivariable logistic regression analyses were performed to determine whether MRI finding was an independent predictor of adverse pathology after RP. Results: The preoperative PSA level, Gleason score and clinical stage showed significant variations between the NST, EST, and SST groups. Tumor suspicion on MRI was significantly associated with primary Gleason pattern, pathologic stage, and surgical margin. On multivariate analysis, MRI findings were independently predictive of primary Gleason score ≥ 4, pathologic stage ≥ T3, and positive margin. Conclusion: Prostate cancer patients with increased tumor suspicion on MRI incorporating T2 and DWI seemed to have worse pathologic features after RP. MRI may have potential use as a surrogate biomarker for adverse pathology.