Safe-R: a novel score, accounting for oncological safe nerve-sparing at radical prostatectomy for localized prostate cancer

Abstract

The objectives of the study were to describe a novel score (safe-R), combining information on surgical margin status (SM) and extend of nerve-sparing (NS) applicable for all patients undergoing radical prostatectomy (RP), and to test the impact of our frozen-section navigated nerve-sparing approach (NeuroSAFE) on safe-R score. We retrospectively analyzed 9,635 RPs performed at our center between 2002 and 2011. Of these, 47 % were conducted with NeuroSAFE. Proportions of NS and SM status were assessed. Subsequently, a score for oncological safe NS (safe-R) was developed; Safe-R was categorized as 3 (for negative SM and bilateral NS), 2 (for negative SM and unilateral NS), 1 (for negative SM without NS), and 0 (for patients with positive SM), respectively. The impact of NeuroSAFE on safe-R was analyzed by chi-square test and confirmed by multinomial logistic regression, adjusting for preoperative risk factors. Applying NeuroSAFE resulted in enhanced safe-R score, indicating lower rates of positive SM and higher rates of NS, across all risk categories (all p < 0.001). For example in high-risk patients, NeuroSAFE resulted in lower proportions of safe-R 0 (27.6 vs. 33.6 %) and higher proportions of safe-R 3 (32.4 vs. 17.1 %, p < 0.001). Linkage between the NeuroSAFE approach and safe-R was confirmed after multinomial logistic adjustment for preoperative risk factors. All results were confirmed in a propensity-matched cohort (matched for preoperative risk factors and year of surgery, data not shown). Safe-R represents a novel tool to assess and report on oncological safe nerve-sparing in RP. NeuroSAFE is associated with enhanced safe-R scores.