Risk factors associated with positive surgical margins following radical prostatectomy for clinically localized prostate cancer: can nerve-sparing surgery increase the risk?

Abstract

Objective: The aim of this study was to evaluate the impact of preoperative and surgical parameters, including nerve-sparing technique, on the risk of positive surgical margins (PSM) following radical prostatectomy for clinically localized prostate cancer.

Material and methods: A prospective consecutive single-institution Danish cohort of 1148 patients undergoing RP between 1995 and 2011 was investigated. To analyse the impact of covariates on risk of PSM, a multivariate logistic regression model was used, including cT category, biopsy Gleason score, prostate-specific antigen (PSA), percentage positive biopsies for cancer (PPB), surgeon and surgical technique.

Results: The overall rate of PSM was 31.4%. The risk of PSM depended (p value for Wald χ(2)) on PSA (p < 0.0001), PPB (p = 0.003), nerve-sparing surgery (p = 0.03) and the surgeon (p < 0.0001). For every doubling of PSA, the risk of PSM increased by 56%, beginning at 0.5 ng/ml [odds ratio (OR) = 1.56, 95% confidence interval (CI) 1.3-1.9, p < 0.01], and every 10% increase in PPB resulted in an 11% increased risk of PSM (OR = 1.11, 95% CI 1.0-1.2, p = 0.002). Two out of the six surgeons had a 50% reduction of risk of PSM compared to the referent surgeon. Nerve-sparing surgery increased the risk of PSM by 50% compared to wide resection (OR = 1.5, 95% CI 1.0-2.1, p = 0.03).

Conclusion: Both preoperative and surgical parameters affect the risk of PSM after radical prostatectomy. Surgeon and high preoperative PSA, PPB and cT category were confirmed as predictors of PSM. Surprisingly, nerve-sparing surgery was independently associated with increased risk of PSM. The correct selection of candidates for nerve-sparing surgery remains unresolved.