(UroToday.com) Positive surgical margins represent a poor prognostic factor at the time of radical prostatectomy.1 However, there have been conflicting results as to the prognostic implications of positive surgical margins in the literature.2 The objective of the current study was to investigate the impact of positive surgical margins, its length, the focality, and the Gleason grade at the positive surgical margins, on the oncologic outcomes in non-organ-confined radical prostatectomy patients. The results of this study were presented by Felix Preisser, MD, and colleagues at the AUA 2020 Virtual Annual Meeting.

For this study, patients who harbored non-organ-confined (pT3) prostate cancer at radical prostatectomy between 2010 and 2016 within a high-volume center database were identified. Notably, only patients without lymph node invasion were included. Kaplan-Meier analyses and multivariable Cox regression models were used to test the effect of positive surgical margins on biochemical recurrence, metastasis and death after radical prostatectomy in patients without adjuvant radiotherapy.

Overall, there were 3,706 patients that were identified, and among these patients, 27.2% (n=1,008) harbored positive surgical margins. Patients with positive surgical margins had higher median prostate-specific antigen (PSA) values (11.0 ng/ml vs. 7.9 ng/ml, p<0.001), higher proportion of primary Gleason ≥4 (56.0% vs. 38.7%, p<0.001) and more frequently harbored seminal vesicle invasion (45.9% vs. 22.0%, p<0.001). At 72 months after radical prostatectomy, biochemical recurrence-free survival was 44.4%, metastasis-free survival was 64.7%, and overall survival was 63.3% for patients with positive surgical margins versus 79.4%, 91.2%, and 93.4% for patients without positive surgical margins, respectively (all p<0.001). Biochemical recurrence-free, metastasis-free and overall survival rates at 72 months were 49.3% vs. 32.7% (p=0.10), 60.9% vs. 76.5% (p=0.70), and 91.3% vs. 98.4% (p=0.30) for unifocal versus multifocal positive surgical margins. Additional results included 62.7% vs. 25.8% (p<0.001), 88.5% vs. 36.1% (p<0.001) and 98.4% vs. 83.7% (p<0.01) for patients with Gleason pattern 3 versus ≥4 at the margin and 48.4% vs. 37.3% (p=0.03), 63.6% vs. 63.1% (p=0.30) and 91.7% vs 93.9% (p=0.90) for <4 mm versus ≥4 mm length of margin. In multivariable Cox models, positive surgical margins was an independent predictor for biochemical recurrence (HR 1.59, 95% CI 1.38-1.83), overall survival (HR 1.70, 95% CI 1.16-2.47), and cancer-specific death (HR 4.34, 95% CI 1.89-9.97). In subgroups of patients with positive surgical margins only, length of positive surgical margins (HR 1.03, p=0.03) and Gleason ≥4 at the margin (HR 1.76, p<0.01) represented independent predictors for biochemical recurrence.

Dr. Preisser concluded the presentation with the following take-home messages:

  • Positive surgical margins represent an independent predictor for worse oncologic outcome in non-organ-confined prostate cancer at radical prostatectomy
  • Gleason ≥4 at the margin was an independent predictor for biochemical recurrence and associated with development of metastasis and death after radical prostatectomy
  • Moreover, length of positive surgical margins was an independent predictor for biochemical recurrence. Next to margin status, Gleason at the margin and its length carry important information that should be reported for the specimen

Presented by: Felix Preisser, MD, University Hospital Frankfurt, Frankfurt, Germany

Written By: Zachary Klaassen, MD, MSc – Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, Twitter: @zklaassen_md at the 2020 American Urological Association (AUA) Annual Meeting, Virtual Experience #AUA20, June 27-28, 2020. 

References:

  1. Ghabili K, Park HS, Yu JB, et al. National trends in the management of patients with positive surgical margins at radical prostatectomy. World J Urol 2020 Jun 19 [Epub ahead of print].
  2. Mithal P, Howard LE, Aronson WJ, et al. Positive surgical margins in radical prostatectomy patients do not predict long-term oncological outcomes: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort. BJU Int 2016 Feb;117(2):244-248.
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