Impact of positive surgical margin length and Gleason grade at the margin on biochemical recurrence in patients with organ-confined prostate cancer

BACKGROUND: Positive surgical margins (PSMs) represent a poor prognostic factor at radical prostatectomy (RP). To investigate the impact of PSM, its length, the focality, and the PSM Gleason, on biochemical recurrence (BCR) in organ-confined RP patients.

METHODS: Within a high-volume center database, we identified patients who harbored organ-confined (pathologic stage T2 disease) prostate cancer (PCa) at RP (2010-2016). Kaplan-Meier analyses and multivariable Cox regression models were used to test the effect of the PSM on the BCR risk.

RESULTS: Overall, 8770 patients were identified. Of those, 6.6% (n = 579) harbored PSM. BCR-free survival at 72 months after RP was 77.7% vs 89.0% for patients with vs without PSM (P < .001). BCR-free survival rates at 72 months were 77.4% vs 73.6% (P = .1) for unifocal vs multifocal PSM, 77.2% vs 71.8% (P = .03) for Gleason pattern 3 vs ≥4 at the margin and 88.4% vs 66.3% (P < .001) for <3 vs ≥3 mm length of margin. In multivariable Cox models PSM was an independent predictor for BCR (hazard ratio [HR] = 2.40, P < .001). However, in subgroups with PSM, only ≥3 mm PSM represented an independent predictor (HR = 1.93, P = .04), while focality and Gleason at the margin were no significant predictors.

CONCLUSION: PSM represents an independent predictor for BCR in organ-confined PCa at RP. Moreover, Gleason ≥4 at the margin and ≥3 mm PSM length were associated with worse BCR-free survival. Closer surveillance of patients with organ-confined PCa at RP and PSM can help to identify those who qualify for early salvage radiotherapy.