The correlation of radical prostatectomy histopatology with multiparametric prostate MRI

Prostate cancer is the most common noncutanous malignancy in men. Before the prostate MRI, only digital rectal examination was used in the clinical staging and was inadequate. If we can predict the presence of seminal vesicle invasion (SVI) and extraprostatic extension (EPE) or tumor size of the prostate cancer, a surgical strategy such as extensive resection and non-nerve sparing surgery may be identified for better oncologic outcomes. Preoperative multiparametric prostate MRI findings and postoperative histopathology specimens of 84 patients who had undergone radical prostatectomy for localized prostate cancer at Hacettepe University Faculty of Medicine Department of Urology between 2011-2018 were compared. Prostate MRI revealed lesion size, extraprostatic extension, seminal vesicle invasion, location and number of lesions, and PIRADS classification. The lesion detected on MRI was classified as less than or greater than 15 mm. Extracapsular extension, seminal vesicle invasion, surgical margin, tumor percentage, pathologic stage, Gleason and ISUP scores were determined according to the pathology specimen evaluation. Data were analyzed in the SPSS 23.0 program. In our study, pathologic EPE was found in 35.7% (30/84) of patients and SVI was found in 22.6% (19/84) of patients. The sensitivity, specificity, PPD, NPD and accuracy of prostatic MRI for EPE were 50%, 88.9%, 71.4%, 76.2% and 75% respectively. The sensitivity, specificity, PPD, NPD and accuracy of prostatic MRI for SVI were 42.1%, 93.8%, 66.6%, 84.7% and 82.1% respectively. In patients with lesion size ≥15 mm, the sensitivity of MRI for SVI increased from 42.1% to 61.5% and the accuracy increased from 82.1% to 91.1%. In multivariate analysis, the lesion ISUP score and diagnostic PSA value were positively correlated with surgical marginal positivity (p = 0.006, HR = 12.433 and p = 0.021, HR = 1.072, respectively). Lesion size was found as a factor predicting pathologic EPU positivity (p = 0.005, HR = 6.131) and presence of SVI in MRI predicted pathologic SVI positivity (p = 0.033, HR = 5.808). The positive surgical margin risk was found to be higher in case of high PSA values, SVI and EPE on MRI, high ISUP grade of the lesion and systematic biopsy, presence of tumor at prostate apex and lesion size ≥15 mm.