Positive Surgical Margin Trends in Patients with Pathologic T3 Prostate Cancer Treated with Robot-Assisted Radical Prostatectomy.

INTRODUCTION We analyzed the trends of positive surgical margin (PSM) location in patients who had pT3 disease at robot-assisted radical prostatectomy (RARP). We aimed to describe our changing incidence of PSMs in the largest series to date of patients with pT3 disease who were treated by RARP. METHODS A single-institution, single-surgeon review was performed of all patients who underwent RARP from 2005 to 2011. Perioperative data were collected for all patients with pT3 prostate cancer from a prospectively maintained RARP database. The PSM incidence and rates were stratified by location. The PSM rates per location were trended over time. RESULTS In total, 2478 consecutive patients underwent RARP between July 2005 and December 2011. Of these patients, 555 were found to have pT3 disease. The PSM rate for patients with pT3 disease was 47%. The PSM rate for patients with pT3a and pT3B disease was 42.8% and 60.6%, respectively. Over the duration of this study, the PSM rate in patients with pT3 disease decreased significantly from 70.6% in 2005 to 32.3% in 2011 (p=0.002). The apical PSM rate showed the greatest decrease during this period going from 52.9% in 2005 to 5.2% in 2011 (p=0.018). CONCLUSION We present the largest series to date involving the treatment of locally advanced prostate cancer initially managed with RARP. Our findings suggest that patients with locally advanced prostate cancer can be treated with RARP with acceptable positive margin rates. Overall PSM rates improved nearly 40% over the 6.5-year period of this study.