Extent of positive surgical margins following radical prostatectomy: impact on biochemical recurrence with long-term follow-up

BACKGROUND: To assess the prognostic value of the extent of positive surgical margins (PSM) following radical prostatectomy (RP) on biochemical recurrence (BR) with long-term follow-up. METHODS: This retrospective study analyzed 1275 RPs performed between January 1992 and December 2013 in two university centers in Marseille (France). The inclusion criteria were: follow-up > 24 months, undetectable postoperative prostate-specific antigen (PSA), no seminal vesicle (SV) invasion, no lymph node invasion confirmed by surgery (pN0) or imaging (pNx), and no neoadjuvant or adjuvant treatment. BR was defined by PSA level ≥ 0.2 ng/mL on two successive samples. We included 189 patients, divided into two groups: - Focal PSM (fPSM): single PSM (sPSM) ≤3 mm; - Extensive PSM (ePSM): sPSM with linear length > 3 mm or several margins regardless of the length. RESULTS: The median follow-up was 101 months (18–283) and the median age was 63 years (46–76). BR occurred in only 12.1% (14/115) of cases involving fPSM and in 54.1% (40/74) of cases involving ePSM. In the multivariate model, ePSM patients were significantly associated with increased BR compared to fPSM (hazard ratio [HR] = 6.11; 95% confidence interval [CI] = 3.25–11.49). The ePSM significantly decreased BR-free survival (p < 0.001) for every patient and every subgroup (pT2, pT3a, pG ≤6, and pG ≥7). The median BR time following RP was significantly shorter for ePSM patients than fPSM (57.2 vs. 89.2 months p < 0.001). CONCLUSION: With a median 8-year follow-up, ePSM was strongly associated with BR compared to fPSM. Therefore, it seems legitimate to monitor patients with fPSM. In cases of ePSM, adjuvant treatment appears effective.