Abstract: PD61-08
Sources of Funding: none

Introduction

Multiple pathologic features have been shown to predict biochemical recurrence (BCR) in patients after radical prostatectomy (RP) for prostate cancer. While positive surgical margins (PSM) have been shown to increase the likelihood of BCR, little data exists on the clinical significance of the tumor Gleason grade at the site of PSM. This study aims to assess if the Gleason grade at the PSM is predictive of BCR, and whether its predictive value differs from that of other commonly referenced risk factors.

Methods

We performed a retrospective review of a prospectively maintained database of all patients who underwent RP at our institution from 2009 to 2015. We identified 403 patients, 58 (14.4%) of whom were noted to have PSM. These cases were reviewed by an attending Pathologist who assigned a Gleason grade (3, 4 or 5) to the tumor at the site of PSM. The predictive value for BCR was compared to that of final pathology Gleason score and presence of PSM alone.

Results

We found that 34.5% (20/58) of patients with PSM had BCR, which was greater than the overall BCR rate of 19.9% (80/403) (p < 0.0001). Patients with Gleason 4+ disease at the PSM had a higher BCR rate (57.9%, 11/19) compared to those with Gleason 3 (23.1%, 9/39, p = 0.009) and those with a negative margin (17.4%, 60/345, p < 0.0001). Interestingly, patients with Gleason 3 at the PSM did not have a significantly higher BCR rate than those with a negative margin. Gleason grade at the PSM was an independent predictor of BCR compared to presence of PSM alone. In patients with Gleason sum 7 disease on traditional final pathology, those with Gleason 3 at the PSM had a lower BCR rate (25.0%, 8/32) compared to those with Gleason 4+ (58.8%, 10/17, p = 0.02).

Conclusions

Our data suggests that Gleason score at the site of PSM independently predicts BCR in patients following RP with accuracy similar to traditional pathologic staging. However, in patients with a PSM and Gleason 7 on traditional pathologic staging, the presence of Gleason 4 or tertiary 5 disease at the margin can serve as an independent predictor of BCR, relative to patients with Gleason 3 at the margin. Routine reporting of the Gleason score at the site of a positive surgical margin may aid in postoperative risk stratification following RP.

Funding

none