mpMRI preoperative staging in men treated with antiandrogen and androgen deprivation therapy before robotic prostatectomy.

Introduction: Using multiparametric magnetic resonance imaging (mpMRI), we sought to preoperatively characterize prostate cancer (PCa) in the setting of antiandrogen plus androgen deprivation therapy (AA-ADT) prior to robotic-assisted radical prostatectomy (RARP). We present our preliminary findings regarding mpMRI depiction of changes of disease staging features and lesion appearance in treated prostate.

Methods: Prior to RARP, men received 6 months of enzalutamide and goserelin. mpMRI consisting of T2 weighted, b = 2,000 diffusion weighted imaging, apparent diffusion coefficient mapping, and dynamic contrast enhancement sequences was acquired before and after neoadjuvant therapy. Custom MRI-based prostate molds were printed to directly compare mpMRI findings to H&E whole-mount pathology as part of a phase II clinical trial (NCT02430480).

Results: Twenty men underwent imaging and RARP after a regimen of AA-ADT. Positive predictive values for post-AA-ADT mpMRI diagnosis of extraprostatic extension, seminal vesicle invasion, organ-confined disease, and biopsy-confirmed PCa lesions were 71%, 80%, 80%, and 85%, respectively. Post-treatment mpMRI correctly staged disease in 15/20 (75%) cases with 17/20 (85%) correctly identified as organ-confined or not. Of those incorrectly staged, 2 were falsely positive for higher stage features and 1 was falsely negative. Post-AA-ADT T2 weighted sequences best depicted presence of PCa lesions as compared to diffusion weighted imaging and dynamic contrast enhancement sequences.

Conclusion: mpMRI proved reliable in detecting lesion changes after antiandrogen therapy corresponding to PCa pathology. Therefore, mpMRI of treated prostates may be helpful for assessing men for surgical planning and staging.