Attempts To Decrease Positive Surgical Margins

Because a significant number of cases reported by Stamey et al.6 had an iatrogenic positive apical margin, some authors have proposed a perineal surgical approach for more accurate dissection of the apex. Weldon et al. reported 7% solitary positive apical margin using perineal prostatectomy.10 The lower incidence of positive apical margin using a perineal approach suggests improved exposure at the apex may be an advantage. Boccon-Gibod et al. performed a retrospective non-randomized study to compare 48 perineal with 46 retro-pubic prostatectomy specimens of identical pathological stage, and concluded that, as far as apical margins were concerned, the perineal approach was a much safer than the retropubic approach.12 However, they also reported that the incidence of positive surgical margins in organ-confined tumors was higher in the perineal than retropubic group (43% vs. 29%). Furthermore, they documented that the incidence of capsular incisions exposing benign glandular tissue was significantly higher in the perineal than retropubic group (90% vs. 37%) irrespective of positive surgical margins. They concluded that, although overall the perineal and retropubic approaches to radical prostatectomy for clinically (T1, T2) localized prostate cancer are similar as far as positive margins and biochemical failure rates are concerned, the retropubic probably is superior to the perineal approach for control of organ-confined cancer.

Ohari reported a steady decline with time in the frequency of positive surgical margin (24% to 8%) at their institution, partly due to improved surgical techniques during radical retropubic prostatectomy.16 Since positive surgical margins occurred more frequently posterolaterally in their series, in the area of neurovascular bundle, they started resecting all or part of the neurovascular bundle more often. They further modified their technique to approach the neurovascular bundle laterally, preserving the bundles more often while allowing a wide dissection around the apex of the prostate, especially posteriorly.

Stephenson et al. reported their experience in 53 non-nerve-sparing radical retropubic prostatectomies performed with attention paid to extending the margin of attached periprostatic tissues.49 They accomplished this primarily by initial perirectal release of periprostatic tissues at the level of longitudinal rectal fibers posterior and lateral to the prostate to ensure that the maximal quantities of periprostatic tissue will remain with the prostate specimen and will not be attenuated or sheared away at subsequent stages of the procedure. Using this technique, they noted a positive surgical margin rate in only 13% and capsular penetration in 89% of cases.

The role of nerve-sparing surgery remains controversial with regard to its association with positive surgical margins. Although postoperative erectile dysfunction is multifactorial, bilateral excision of neurovascular bundles to reduce postoperative positive surgical margins compromises postoperative potency. Several reports have suggested nerve-sparing techniques do not significantly increase the rate of positive surgical margins.6'33 Partin etal. reported that, although wider excision of the neurovascular bundles in an attempt to obtain a negative margin may delay recurrence initially, most patients with established capsular penetration ultimately failed radical prostatectomy despite wide excision of periprostatic soft tissue by the end of 43 months.48 In men with any apical or near apical nodule, Stamey etal. recommended wide excision of the adjacent periprostatic tissue, including each neurovascular bundle.5

In an attempt to improve urinary continence, several investigators have advocated dissecting the prostate away from the bladder so as to preserve the fibers of the bladder neck.50 One problem with such bladder neck-sparing procedures is that tumor may be left in the unresected tissue of the bladder neck. Gomez etal. noted that 6% of patients will have a positive margin at the bladder neck in radical prostatectomy specimen when a bladder neck sparing technique is used.27 Wood et al. performed circumferential bladder neck biopsies in situ after bladder neck-sparing radical prostatectomy and found 12% of patients had a positive surgical margin.25 In their study, the posterior bladder was the most common site of bladder neck involvement accounting for 70% of the positive finding. They recommended frozen section analysis of biopsy specimen from the posterior bladder neck at the 4, 6 and 8 o'clock positions to identify residual benign tissue or prostate cancer before the vesicourethral anastomosis is performed. Licht et al. noted a positive bladder neck margin of 6.8% in 206 patients with bladder neck preservation, which was associated in all with higher grade tumor, more advanced local stage and other positive margin sites.51 However, local recurrence and PSA failure rates were independent of bladder neck preservation or resection.

Since prostate cancer is sensitive to hormonal manipulation, surgeons have attempted to overcome the problem of positive surgical margins by advocating neo-adjuvant hormonal treatment for locally advanced tumors.52 The development of gonadotropin-releasing hormone agonists and antiandrogens provided the possibility of reversible androgen blockade, which was given as 3-month pretreatment before radical prostatectomy. These agents made induction therapy possible without the cardiovascular risks associated with diethylstilbestrol or the disadvantages of orchiectomy. Many investigators have reported downstaging and even downgrading of the tumor using this approach with gonadotropin-releasing hormone analog, with or without and antiandrogen in randomized trials.

Both non-randomized and randomized studies have reported a decrease in positive surgical margins after hormonal pre-treatment. Soloway etal. noted that the rate of positive surgical margins was six fold less in patients treated with hormonal therapy than in those who underwent only radical prostatectomy for clinical T2b disease.53 Goldenberg etal. reported the results of the Canadian Urologic Oncology Group in patients with stage T1-T2 prostate cancer and similarly found that neoadjuvant hormonal therapy decreased the rate of positive surgical margins from 65% in the surgery group to 28% in the hormonal therapy group.54 However, Aus reported that, even though early progression was delayed by approximately a year in the pretreatment group, at a median follow-up of 3 years, there was no difference in progression-free survival between the two treatment arms.55

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