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A Retrospective Cohort Analysis of Positive Margin Rates in Open vs Robotic-Assisted Laparoscopic Prostatectomy at Brown University
Simone Thavaseelan, MD1, Michelle Gaudreau, RN, BSN, CCRP2, George Haleblian, MD1, Gyan Pareek, MD1, Renzulli Joseph, MD1.
1Brown University, Providence, RI, USA, 2The Miriam Hospital, Providence, RI, USA.

Background:
Robotic Assisted Laparoscopic Radical Prostatectomy (RALRP) has surpassed open prostatectomy (OP) as the most commonly performed surgical procedure for localized prostate cancer. Recently published literature from our institution demonstrates that RALRP is associated with major and minor complication rates of 5% and 17%, respectively. Oncologic control is one of the most significant primary end points in prostate cancer therapies. Pathologic margin status has been deemed appropriate to use as a surrogate for higher incidence of postoperative PSA recurrence. The objective of this study is to compare the Gleason grades and positive surgical margin rates of patients treated with RALRP compared to OP and to determine if there is a difference between OP and RALRP at our institution.
Methods:
A total of 262 consecutive patients who underwent OP were evaluated from 2004 to 2006 from an IRB approved retrospective database accrued by an independent third party committee. Similarly a total of 446 consecutive patients who underwent RALRP were evaluated from 2006 to 2009 from an IRB approved prospective database accrued by an independent third party committee. These two groups were compared with regards to percentage of cases performed stratified by Gleason Score. Additionally positive surgical margin rates per year for OP and RALRP were assessed.
Results:
Stratified by OP vs RALRP approach and by Gleason Score, the average percentage of OP performed from 2004 to 2006 was 52.3% (Gleason 3+3), 32.9% (Gleason 3+4), 8% (Gleason 4+3) and 2.5% (Gleason 4+4).
Stratified by OP vs RALRP approach and by Gleason Score, the average percentage of RALRP performed from 2006 to 2009 was 42.4% (Gleason 3+3), 46.7% (Gleason 3+4), 7.9% (Gleason 4+3) and 1.5% (Gleason 4+4).
Statistical analysis using Chi square test revealed a significant difference (p=0.0267) between OP (52.3%) and RALRP (42.4%) for Gleason 6 (3+3) cases in favor of OP.
Statistical analysis using Chi square test revealed a significant difference (p=0.0267) between OP (32.9%) and RALRP (46.7%) for Gleason 6 (3+4) cases in favor of RALRP.
As seen in Figure 1, positive surgical margin rates for OP were 27.3%, 18.3% and 31.4% from 2004, 2005, and 2006 respectively.
Positive surgical margin rates for RALRP were 21.5%, 15.3% and 13.6% from 2007, 2008, and 2009 respectively.
Conclusions:
RALRP has been established as a safe surgical approach to prostate cancer. Oncologic success is often extrapolated from postoperative positive margin rates. Higher risk prostate cancers are expected to result in higher rates of extracapsular extension and positive margins. However, our RALRP positive margin rate decreased over time despite a higher percentage of intermediate risk disease (3+4) that was taken to RALRP as compared to the open cohort suggesting that excellent oncologic outcomes were achieved with RALRP at our institution.
Figure 1: Positive Surgical Margin Rates for Open prostatectomy versus RALRP

OpenRALRP
200427.321.52007
200518.315.32008
200631.413.62009

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