Predictors of positive surgical margins after radical prostatectomy at a single institution: preoperative and pathologic factors, and the impact of surgeon variability and technique on incidence and location.

INTRODUCTION: To identify and assess predictive factors for positive surgical margins (PSM) in patients undergoing radical prostatectomy (RP).
MATERIALS AND METHODS: An Institution Review Board (IRB) approved retrospective review of 1751 patients that underwent RP from March 2000 to June 2013 was performed. Identified were 1740 patients whom had not received neoadjuvant therapy; these were used for the purpose of this analysis. Univariate and multivariate analysis were performed to determine factors associated with and predictive of PSMs, divided into preoperative and pathological. Variables analyzed include age, body mass index (BMI), race, surgeon, surgical modality, pathologic T-stage and Gleason sum, extracapsular extension (ECE), seminal vesicle involvement (SVI), perineural invasion (PNI) and prostate weight. Finally, each surgical technique was analyzed to determine the most common site of PSM.
RESULTS: Rate of PSM was 23.6%. Our analysis showed that preoperative prostate-specific antigen (PSA) level ≥ 10ng/mL, and pathologic T3/T4-stage and PNI significantly predicted PSM. Age > 60 years and prostate weight > 60 g were predictive against PSM. Gleason score ≥ 7 and PSM were significant risk factors for biochemical recurrence (BCR). Surgical approach did not affect the rate of PSM. Open RP was associated with a higher apical PSM rate (38.5%) and robotic RP with a higher posterolateral PSM rate (52.3%).
CONCLUSIONS: High preoperative PSA levels, and advanced TNM-staging predicted positive surgical margins in our cohort. Patients with PSM were subsequently found to have higher risk of BCR.