INITIAL DISSECTION OF THE LATERAL FASCIA REDUCES THE POSITIVE MARGIN RATE IN RADICAL PROSTATECTOMY

Objectives. Positive margins predict an adverse outcome after radical retropubic prostatectomy (RRP). The effect of initial incision of the lateral pelvic fascia prior to urethral transection on positive margin s rates is assessed. Methods. The rate of positive margins in 350 cons ecutive RRPs is compared in two groups without hormonal pretreatment. In group 1 (n = 198), RRP was performed in standard fashion with apica l dissection and urethral transection preceding dissection of the late ral pelvic fascia and mobilization of the prostate from the anterior r ectal surface. In group 2 (n = 152), the initial step consisted of inc ision of the lateral pelvic fascia along the perirectal surface with p rostatic mobilization off the rectum prior to urethral transection. Th e bladder neck and seminal vesicle dissection was identical in both gr oups. Specimens were step-sectioned for histologic analysis. Differenc es in rates of positive margins were analyzed by Fisher's exact test a nd logistic regression. Results. The rate of positive margins was redu ced from 37.4% in group 1 to 15.8% in group 2. In the logistic regress ion model, surgical technique, Gleason sum, serum prostate-specific an tigen (PSA), and the presence of extracapsular extension were independ ent predictors of margin status, with group 1 being more than twice as likely to have positive margins than group 2 (P = 0.0076; odds ratio 2. 198; 95% confidence interval 1.23 to 3.92). The rate of positive ma rgins was reduced from 45.5% in group 1 to 16.7% in group 2 (P = 0.004 6) for non-nerve-sparing RRP and from 33.3% to 15.5% (P = 0.0012) for nerve-sparing RRP. There were no differences in functional outcomes be tween groups and no rectal injuries in group 2. Conclusions. Initial d issection of the lateral pelvic fascia during RRP results in a lower r ate of positive margins independent of tumor grade, clinical stage, ex tracapsular extension, and preoperative PSA level. (C) 1998, Elsevier Science Inc. All rights reserved.