Influence of nerve-sparing (NS) procedure during radical prostatectomy (RP) on margin status and biochemical failure

Abstract

Purpose: To evaluate whether nerve-sparing procedure itself is a risk factor for biochemical recurrence in carefully selected patients.

Material and methods: We compared patients of our historical series who in retrospect were candidates for nerve-sparing (NS) procedure with a contemporary cohort of patients. With respect to stage migration and selection bias between these two groups we performed a multivariate analysis adjusting for all explanatory variables in the model. NS was performed in n = 723 patients (bilateral n = 359, unilateral n = 364) in comparison to n = 620 patients undergoing non-NS RP, comprising n = 756 patients within the favorable pT2 category. We examined the association of clinical and histopathological parameters in relation to PSA recurrence in uni- and multivariate analyses including NS as a variable. Furthermore, for each prostate lobe separately we determined whether surgical procedure (nerve-sparing vs. non-nerve-sparing RP) resulted in a positive margin.

Results: In univariate analysis there was no difference in pT2 (log rank p = 0.091), pT3a (log rank p = 0.171) and pT3b (log rank p = 0.110) cancers between patients treated with NS compared to non-NS surgery. The 3- and 5-year recurrence free survival rate for patients with pT2, pT3a and pT3b cancers treated by NS vs. non-NS were 96.3/94.9 vs. 94.9/90.8, 75.0/61.8 vs. 73.4/55.0 and 46/30 vs. 38/23. Multivariate regression analysis showed no association with PSA failure (p = 0.798) for patients who underwent NS. Capsular penetration (p < 0.001), lymph-node status (p < 0.001), seminal vesicle invasion (p < 0.001), surgical margin status (p = 0.0130), Gleason score (p < 0.001) and preoperative PSA (p = 0.005) were significantly associated with risk of failure. The positive margin rate per each prostate lobe in pT2 cancers was 6.5% vs. 5.1% in NS and non-NS cases, 10.3% vs. 17.3% in patients with extracapsular extension and 15.0% vs. 25.1% in cases with seminal vesicle invasion respectively.

Conclusion: NS RP is an oncologically safe procedure provided that appropriate preoperative selection of patients by means of a validated nomogram is performed. Moreover, evaluation of positive margins in patients undergoing NS and non-NS RP revealed no evidence that adequacy of tumor excision is compromised by NS procedure.