Evaluation of preoperative prostate magnetic resonance imaging for cancer control and neurovascular tissue preservation during robotic radical prostatectomy.

Abstract

101 Background: Prostate multi-parametric magnetic resonance imaging (mpMRI) can precisely depict prostate cancer (PCa) location and adverse pathologic features. Surgeons can utilize this information to maximize sparing of the neurovascular bundles (NVBs) during radical prostatectomy (RP) while avoiding a positive surgical margin (PSM). We detail the technique of using preoperative mpMRI to quantify its effect regarding nerve-sparing and rates of PSMs. Methods: A prospectively maintained database was queried for robotic-assisted RPs (RARPs) with preoperative mpMRI between 2007-2017. Imaging margin risk factors (iMRF) were defined on mpMRI as frank extraprostatic extension (EPE), possible EPE, and capsular irregularity (capsular bulge, lesion-capsule contact, or lesion adjacency to the neurovascular bundles). Surgical adjustments to nerve-sparing technique (full sparing, partial sparing, and wide excision) were made based on these findings. Results: Five hundred thirty-two patients comprising 1041 prostate sides were included for analysis. Overall, PSM rate was found in 80/1041 (7.7%) sides of the prostate. iMRF were seen in 313/1041 (30.1%) prostate sides, for which adjustments were made in 244/313 (78.0%) of these. In the 69/244 (22.0%) cases where full nerve-sparing was performed despite iMRF, PSM rate was 20/69 (29%) compared to 33/244 (13.5%), p = 0.002. MRI-guided surgical adjustments decreased PSM risk by 68% and 15% in pT3 and pT2 cases, respectively. On multivariable analysis, logPSA (odds ratio [OR] 4.06, [95% CI 2.40-12.3], p < 0.001) and iMRF (OR 1.78, [95% CI 1.01-3.16], p = 0.047) were significantly associated with PSM while nerve-sparing adjustment was significantly associated with decreased risk of PSM (OR 0.38 [95% CI 0.22-0.66], p = 0.001). Conclusions: MRI effectively detects risks for PSM and guides surgical adjustments to decrease PSM rates. As prostate MRI is more frequently acquired for PCa screening and biopsy, we show its additional value for RP planning and potentially improved outcomes.