Multiparametric MRI in planning of organ-sparing robot-assisted radical prostatectomy for treatment of localized prostate cancer with low and intermediate risk of progression

Abstract

The study objective is to study the role of multiparametric magnetic resonance imaging (mpMRI), to predict extracapsular extension, infiltration of the seminal vesicles, neurovascular bundles and status of positive surgical margin (PSM) in robot-assisted radical prostatectomy (RARP) with fascio- and nerve-sparing and anatomy-sparing techniques in patients with low and intermediate oncological risk; to evaluate safety of RARP with anatomy-sparing techniques in the context of oncological results in the studied patient cohort.Materials and methods. Fifty-four males underwent mpMRI in the device with magnetic field density 3 Tesla without endorectal coil. Results of mpMRI were analyzed using PI-RADS v.2. Prostate-specific antigen level, results of prostate biopsy, nomogram were analyzed. All patients were included into groups with low and intermediate oncological risk. The patients underwent RARP with anatomy-sparing techniques. Gross specimen removed during the surgery was stained with tissue stain DECOLA and subjected to stepwise pathomorphological analysis. Comparative analysis of tumor lesion localization was performed for mpMRI and pathomorphological examination. The study concentrated on the largest tumor lesion locations. The anterior surface of the prostate was examined in detail. Patients were classified per risk groups in accordance with the National Comprehensive Cancer Network (NCCN) and D'Amico criteria.Results. Full or partial overlap of the lesions per mpMRI and pathomorphological examination were observed in 48 (88.9 %) patients; locations of tumor lesions disagreed in 6 (11.1 %) patients. PSM was detected in 8 (14.8 %) patients; among them in 7 (12.9 %) the size was between 0.1 and 0.4 cm. On the anterior surface of the prostate 3 (5.5 %) PSM were observed, 2 of which were between 0.14 and 0.4 cm, 1 was multifocal, larger than 0.3 cm. Per mpMRI results and histological examination, the anterior surface (fibromuscular stroma) was affected in 14 (25.9 %) and 11 (20.4 %) cases, respectively. Among them, lesion locations overlapped in 11 observations. Results of anatomy-sparing RARP show increased PSM rate compared to traditional nerve-sparing based on the anterior surface of the prostate.Conclusion. Routine mpMRI for patients who are planned to undergo RARP allows to justify selection of anatomy-sparing RARP or rejection of modification in favor of more thorough dissection. mpMRI plays a significant role on planning of anatomy-sparing RARP, achievement of negative surgical margin in patients with low and intermediate risk of oncological progression. Evaluation of the location and size of cancer lesion in the prostate allows to plan for special aspects of anatomy- and/or nerve-sparing techniques, achieve lower PSM rate, optimize oncological and functional surgical results in localized prostate cancer.

Keywords

• prostate cancer
• multiparametric magnetic resonance imaging
• robot-assisted radical prostatectomy
• nerve-sparing prostatectomy
• organ-sparing prostatectomy