[839] Identification of Extraprostatic Extension at Apical Margin: A Retrospective Review of 568 Robot-Assisted Radical Laparoscopic Prostatectomies

N Mourtzinos, DE Sutherland, AM Schwartz, FJ Bianco, MK Rezaei. The George Washington University, Washington, DC

Background: The boundary between the prostate and the surrounding tissue is ambiguous and causes difficulty in identifying extraprostatic extension (EPE) in many cases. This problem is further confounded in the apex of the prostate where the benign glands are intermingled with skeletal muscle, creating more difficulty and controversy in recognizing EPE. Even more problematic is to determine whether positive surgical margins (PSM) are due to capsular incision (CI) into the tumor or EPE. Recent revisions to address these issues have been published (Chuang and Epstein, 2008 and Epstein, et al, 2005).
Design: A total of 568 robot-assisted laparoscopic radical prostatectomy procedures were performed between 2004 and 2007 at our institution. Two hundred fourteen patients had either EPE, PSM or both. Among this group, forty-six cases were originally labeled as PSM at apical margin, either as a sole finding or along with other sites of EPE and PSM. Applying the revised criteria to identify EPE at apex, these cases were re-classified as shown below in Table 1.
Results: The results are shown in the table below:

Original Diagnosis	Revised Diagnosis
	Apical CI (n=19)	Apical PSM@EPE (n=27)
Apical PSM only (23)	13	10
Apical PSM + PSM @ other sites (8)	5	3
Apical PSM + EPE @ other sites (15)	1	14

Using the revised criteria, 60% of our cases (27/46), originally diagnosed as apical PSM, regardless of additional findings, were due to EPE versus CI. Of more clinical significance are the two subsets of patients, initially classified as organ-confined disease (pT2), who are now upstaged to pT3, including 44% (10/23) of patients with apical PSM only and 38% (3/8) of patients with PSM at apex as well as other sites. Although a stage upgrade is not achieved in the subset of patients with EPE at other sites, the data clearly shows the probability of PSM due to EPE at apex is much higher (93% or 14/15) when compared to CI.
Conclusions: Our data supports that utilizing the revised criteria for recognizing EPE at apical margin prevents underestimation of EPE, a prognostically significant finding, and more accurately reflects the clinical stage of the disease. The probability of apical EPE is markedly increased with EPE at other prostatic sites.
Category: Genitourinary (including renal tumors)

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 130, Tuesday Afternoon