[757] Focal and Diffuse Positive Surgical Margins in Radical Prostatectomies (RP): How Should Be Quantitated?

Athanase Billis, Luciana Meirelles, Leandro LL Freitas, Ana GE Duarte, Carlos AM Silva, Marcelo AM Busson, Luis A Magna, Leonardo O Reis, Ubirajara Ferreira. School of Medicine, University of Campinas (Unicamp), SP, Brazil; School of Medicine, University of Campinas, Unicamp, SP, Brazil

Background: Extent of margin positivity in RP correlates with time to biochemical recurrence (TBCR) in most studies. However, during the ISUP consensus conference on handling and staging of RP specimens, no consensus could be reached as to what definition to use for focal and diffuse margin positivity. In this study we propose a simple method for surgical margin extent evaluation.
Design: The study was based on 300 whole-mount consecutive surgical specimens. Each transversal section of the prostate was subdivided into 2 anterolateral and 2 posterolateral quadrants. Using the cone method, 8 sections from the bladder neck and 8 sections from the apex were obtained. Margin positivity was stratified into 2 groups: present up to 2 quadrants and/or sections from the bladder neck or apex (group 1: focal) and in more than 2 quadrants or sections (group 2: diffuse). The groups were compared according to several clinicopathological variables: age, preoperative PSA, RP Gleason score, RP tumor extent using a semiquantitative point-count method, seminal vesicle invasion (SVI), and biochemical recurrence following surgery defined as PSA ≥ 0.2ng/mL. TBCR was analyzed with the Kaplan-Meier product-limit analysis using the log-rank test for comparison between the groups and prediction of TBCR using univariate and multivariate Cox proportional hazards model.
Results: Positive margins were present in 128/300 (42.7%) patients, 65/300 (21.7%) present in group 1 and 63/300 (21%) in group 2. Group 2 tumors were significantly more extensive (p<0.01). There was no significant difference related to age, preoperative PSA, RP Gleason score, and SVI. In 5 years of follow-up, 70% of patients with negative margins, 60% of patients with positive margins in group 1, and 37% of patients in group 2 were free of biochemical recurrence (log-rank, p<0.01). In univariate Cox regression analysis, group 1 was not predictive of TBCR (p=1.65); group 2 was predictive in univariate (p<0.01) as well as in multivariate (p<0.01) analyses.
Conclusions: In whole-mount surgical specimens, only positive margins in more than 2 quadrants and/or sections from the bladder neck or apex significantly predicted time for biochemical recurrence following radical prostatectomy in univariate and multivariate analyses. This is an easy and valuable method for reporting and quantitating focal and diffuse positive surgical margins.
Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 1:00 PM

Poster Session II # 121, Monday Afternoon

 

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