[807] An In-Depth Study of Extraprostatic Extension and Margin Status in Radical Prostatectomies

S Chan, F Garcia, M Moussa, J Chin, M Gabril. LHSC/UWO, London, ON, Canada

Background: In radical prostatectomies for prostate cancer (PCa), a positive margin is defined as tumor in contact with the inked resection margin. Extraprostatic extension (EPE) signifies tumor extending outside the normal confines of the prostate. In this study, we aim to determine the prognostic significance of EPE and positive margins in combination and independently, EPE focality and EPE subtypes.
Design: 148 radical prostatectomies (without neoadjuvant therapy) performed by a single surgeon at our institution (1993-2001) were identified as having EPE/capsular invasion or positive margins. All slides were reviewed and pathological features (Gleason score, PCa volume, seminal vesicle & lymphovascular invasion, lymph node metastasis, margin status and EPE including focality (focal=1 slide, non-focal≥2 slides) and subtype (abut/admixed with fat, level of fat, neurovascular bundle involvement, beyond confines, bulging nodule)) were recorded. Clinical data (age, PSA, biochemical failure, metastasis and survival) was also collected. Cases were subdivided into 4 groups: 1.+EPE only 2.+Margin only 3.+EPE&Margin 4.–EPE&Margin (control).
Results:

Multivariate Statistical Analysis of 4 Groups is Summarized in Table 1

	+EPE only (n=47)	+Margin Only (n=23)	+EPE&Margin (n=38)	Control (n=40)	P Value
%Biochemical Failure (3-160 mo)	42	28	58	13	<.001
%Metastasis	19	0	24	0	<.001
%Survival (1-6 yrs)	91	100	85	100	.027

Biochemical failure (P<.252), metastasis (P<.790), survival (P<.484) rates between +EPE only and +EPE&Margin groups are statistically insignificant

EPE Focality: Non-focal EPE is present in 89% of cases with metastasis and in 89% of cases with death due to PCa. Subtypes: 94% of cases with metastasis and 89% of cases with death have tumor abutting/admixed with fat. 72% of cases with metastasis and 78% of cases with death have neurovascular bundle involvement.
Conclusions: Our data indicates that the presence of EPE regardless of margin status plays an important role in predicting metastasis and death due to PCa, whereas, positive margins in the absence of EPE does not. Clinically, this may suggest that EPE should be given greater importance than positive margins when determining prognosis and treatment. We also find that non-focal EPE is far more common in cases of metastasis and death than focal EPE. Additionally, of the EPE subtypes, tumor abutting/admixed with fat is the most consistent predictor of metastasis and death.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 11:30 AM

Platform Session: Section A, Tuesday Morning