[1025] Skeletal Muscle Involvement by Limited Gleason Score 3+3=6 Cancer on Needle Biopsy Is Not Associated with Adverse Findings at Radical Prostatectomy (RP)

H Ye, JI Epstein. The Johns Hopkins Hospital, Baltimore

Background: When cancer is found in skeletal muscle at the apex at RP, it is controversial whether it represents extraprostatic extension (EPE), since prostatic boundaries are ambiguous in this region with benign prostatic glands naturally blending with skeletal muscle of the urogenital diaphragm. RP apical margins are frequently positive as surgeons try to preserve urogenital diaphragm and to avoid postoperative incontinence. It remains unknown whether skeletal muscle involvement by otherwise not high risk cancer in apical needle biopsies correlates with EPE and margin positivity at RP.
Design: 40 patients underwent RP (2000-2009) after they were diagnosed as Gleason score 6 cancer involving skeletal muscle in one positive needle core only and with the cancer occupying up to 20% of the core (SKEL group). Another 82 RPs were selected where the needle biopsy showed apical cancer with the same criteria, except lacking skeletal muscle involvement (CONTROL group).
Results: Among the 40 SKEL patients, positive cores were labeled as from the apex in 22 and only “left” or “right” in the remaining 18 cases. There was no significant difference in pre-RP data including mean patient age, mean serum PSA values, suspicious digital rectal exam, mean cancer percentage in the positive core, and mean time span between biopsy and RP, between the SKEL and CONTROL groups.

Radical Prostatectomy Findings

	Gleason Score>6	EPE	Margin Positive
SKEL	15.0%	7.5%	12.5%
CONTROL	20.7%	11.0%	4.9%

There were no statistically significant differences between the 2 groups in terms of the RP Gleason score, EPE, or margins. 2/40 SKEL cases and 4/82 CONTROL cases had EPE at apex. Most margin positive SKEL cases had positive margins limited to the apex (4/5). The higher positive margin rate in the SKEL group, although not statistically significant (p = 0.13) may have been due to the skill level of surgeons, as most SKEL patients received RP at outside hospitals.
Conclusions: Limited cancer involvement of skeletal muscle in biopsy specimens should not be used as a contraindication for RP treatment for otherwise resectable prostate cancer as most patients will have organ-confined disease and negative margins.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 110, Tuesday Afternoon