Patterns of positive surgical margins after open radical prostatectomy and their association with clinical recurrence.

Background: We report long-term oncologic outcomes in patients with positive surgical margins (PSMs) at radical prostatectomy (RP) and the oncologic impact of different scenarios of PSMs presentation.

Methods: We selected 494 men with at least 3 years follow-up after surgery. PSMs patterns were recorded as: burden (focal vs. multifocal), site (apical-anterior vs. posterolateral vs. base-bladder neck vs. multiple) and side (unilateral vs. bilateral). Kaplan-Meier curves depicted the clinical recurrence-free survival (CR-FS) rates at 10-year in the overall population, after biochemical recurrence and according to different PSMs patterns. Multivariate Cox-regression analysis was performed to predict CR.

Results: Overall, PSMs sites were apical-anterior, postero-lateral, base-bladder neck and multiple in 19.8%, 23.7%, 3.4% and 43.8%, respectively. Out of 494 patients, 278 (56.3%) had a focal margin, while 216 (43.7%) had a multifocal margin. In 268 (54.3%) and 87 (17.6%) men, PSMs were unilateral and bilateral, respectively. Median follow-up was 93 months. No significant differences were found in CR-FS rates after stratifying according to burden and site of PSMs. Men with unilateral PSMs experienced significant higher CR-FS rates compared to those with bilateral PSMs (87.1% vs. 71.3% at 10 years, P<0.001). At multivariate Cox regression Gleason score 8-10 (HR: 2.53, Confidence Interval [CI]: 1.01-6.33; P=0.04), pathologic stage pT3b-pT4 (HR 3.02, CI: 1.60-7.85; P=0.02) and adjuvant radiotherapy (HR: 0.30, CI: 0.11-0-86; P=0.02) were independent predictors of CR.

Conclusions: Men with bilateral PSMs had higher risk to experience CR, suggesting that the different patterns of PSMs, should be considered during patients counseling to guide postoperative treatments. Retrospective nature of the study and restricted number of patients included consist of main limitations.