Introduction

Nerve sparing (NS) procedures have demonstrated improved potency preservation in radical prostatectomy (RP). A better understanding of prostate neuroanatomy and advancement in surgical techniques has moved from the “all-or-none� concept to a graduated NS to get the best compromise between cancer control and functional outcome. However, the preoperative planning of a NS approach is mostly based on subjective pre or intraoperative variables. Our aim is to provide a user-friendly statistical tool, with a decision rule, to standardize decision making in grading the NS approach.

Methods

A total of 11794 prostatic lobes, from a cohort of 6360 patients who underwent robot-assisted RP between January 2008 and January 2016 in a high-volume centre have been evaluated. _x000D_ The amount of extracapsular extension (ECE) maximum width of every prostatic lobe was calculated. _x000D_ Clinicopathological features were included in a statistical algorithm. Five multivariable models were estimated for: presence of ECE and ECE width greater than 1, 2, 3, and 4 mm. A five­zone decision rule is proposed. Using a graphical interface surgeons can view pre-treatment characteristics and a curve showing the estimated probabilities for ECE amount and the areas identified by the decision rule.

Results

Out of 6360 patients, 1803 (28.4%) were affected by non organ confined disease. Of 11794 prostatic lobes, ECE was present in 1351 lobes (11.4%) and was extended beyond the prostatic capsule for more than 1, 2, 3, 4 mm in 498 (4.2%), 261 (2.2%), 148 (1.3%), 99 (0.8%) cases, respectively. The width of ECE was up to 15 mm (IR 1.00 - 2.00)._x000D_ The 5 logistic models showed good predictive performance? the area under the ROC curve was: 0.81 for ECE, and 0.84, 0.85, 0.88, and 0.90 for ECE width greater than 1, 2, 3, and 4 mm, respectively._x000D_ The proposed graphical tool provides valuable support to the surgeon in the choice of the side-specific surgical strategy and in the counseling with the patient.

Conclusions

Our predictive tool based on 7 variables can accurately predict the presence and the amount of ECE in prostate cancer. Furthermore, a graphical interface supports surgeons in patient counselling and in the choice of the side-specific surgical strategy (Fig.1)._x000D_

Funding

none