Impact of positive surgical margin length and Gleason grade at the margin on oncologic outcomes in patients with nonorgan-confined prostate cancer

Abstract

Purpose: positive surgical margins (PSM) represent a poor prognostic factor at radical prostatectomy (RP). To investigate the impact of PSM, its length, the focality and the Gleason grade at the PSM, on the oncologic outcomes in nonorgan-confined RP patients. Methods: within a high-volume center database, we identified patients who harbored non-organ-confined (pT3) prostate cancer (PCa) at RP between 2010 and 2016. Only patients without lymph node invasion were included. Kaplan–Meier analyses and multivariable Cox regression models were used to test the effect of PSM on biochemical recurrence (BCR), metastasis, and cancer-specific death after RP in patients without adjuvant radiotherapy. Results: overall, 3705 patients were identified. Of those, 27.2% (n = 1007) harbored PSM. At 96 months after RP, BCR-free, metastasis-free and cancer-specific survival was 41.6 versus 57.5%, 82.7 versus 88.6%, and 94.7 versus 98.5% for patients with versus without PSM (all p < 0.001). BCR-free, metastasis-free and cancer-specific survival rates at 96 months were 56.7 versus 26.5% (p < 0.001), 94.4 versus 67.4% (p < 0.001), and 100.0 versus 87.1% (p < 0.01) for Gleason pattern 3 versus ? 4 at the margin and 45.0 versus 27.8% (p < 0.01), 83.3 versus 82.3% (p = 0.2), and 95.2 versus 92.7% (p = 0.3) for <4 mm versus ?4 mm length of margin. In multivariable Cox models PSM was an independent predictor for BCR (hazard ratio [HR]:1.53, p < 0.001) and cancer-specific death (HR:2.75, p = 0.02). In subgroups of patients with PSM only, Gleason ? 4 at the margin (HR:1.60, p < 0.01) and length of PSM (HR:1.02, p < 0.05) was an independent predictor of BCR. Conclusion: PSM represents an independent predictor for worse oncologic outcome in nonorgan-confined PCa at RP. Gleason ? 4 at the margin was associated with the development of BCR, metastasis, and with cancer-specific death after RP. Next to margin status, Gleason at the margin and its length carry important information that should be reported for the specimen.