[848] Do Robotic Prostatectomy Positive Surgical Margins Occur in the Same Location as Extraprostatic Extension?

Matthew T Johnson, Geoffrey N Box, David S Sharp, Ahmad Shabsigh, Ronney Abaza, Debra L Zynger. The Ohio State University Medical Center, Columbus

Background: The frequency of positive surgical margins (PSM) is higher in prostatectomies with extraprostatic extension (EPE). In some cases with organ confined tumor, PSM may reflect incomplete surgical resection. EPE could indicate that complete tumor resection is difficult, therefore resulting in PSM. The goal of this study was to evaluate cases with both EPE and PSM to determine if the locations are concordant.
Design: We conducted a retrospective review of 997 robotic prostatectomies performed at our institution between March 2007 and July 2009 and identified prostatectomy specimens with both EPE and PSM. Prostates had been entirely submitted and processed in whole mount format per our institutional standard protocol. All whole mount slides were then re-reviewed by a genitourinary pathologist. The prostate was subdivided into 8 regions (anterior apex, posterior apex, anterior mid, anteriolateral mid, posterior mid, posteriolateral mid, anterior base and posterior base) and all locations of EPE and PSM were recorded, as well as the size of the largest focus of EPE and PSM.
Results: 5% (50/997) of robotic prostatectomy specimens had both EPE and PSM. In this subset, the predominate Gleason score was 7 (Gleason 7, 74%; 8, 10%; 9, 16%), average volume of carcinoma was 41% (range 15-95%) and pathologic stage was pT3 (pT3a, 62%; pT3b, 38%). Analysis of cases with concurrent EPE and PSM revealed that EPE occurred most commonly at the mid prostate (apex, 11%; mid, 56%; base, 33%), particularly mid posterolateral (29%). In contrast, PSM was most frequent at the base (apex, 27%; mid, 24%; base, 49%). 66% of cases had EPE and PSM in discordant locations, 20% had EPE and PSM in the same location, and 14% had areas in which EPE and PSM were in the same location but also had other areas of discordant EPE and PSM. The average largest focus of EPE was 0.35 cm (range 0.005-1.2 cm, median 0.2 cm) and the average PSM was 0.33 cm (range 0.0015–1.2 cm, median 0.1 cm).
Conclusions: In this study of robotic prostatectomy specimens with concomitant EPE and PSM, PSM more frequently occurs in a location without EPE. EPE was most frequent in the posterolateral mid prostate, while the PSM was most common in the prostatic base. A better understanding of where PSM occur may help guide surgical technique to decrease residual tumor.
Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 1:00 PM

Poster Session II # 131, Monday Afternoon


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