There are two traditional approaches to the prostate for its total removal, retropubic and perineal. Throughout the world, the large majority of total (or so-called radical) prostatectomies are undertaken by the retropubic route with perineal prostatectomy performed by only a small number of urologists. The procedure of perineal prostatectomy is suited particularly to the removal of smaller prostates.
Contemporary surgical management of prostate cancer has been shaped by two seminal events, development of the anatomic RRP by Walsh (393) and application of serum PSA as a means for early detection, resulting in many more young men being diagnosed with this condition than ever before. Consequently, there has been a concerted effort to improve long-term cancer control together with preservation of urinary and sexual function. Description of the anatomic RRP has improved understanding of prostatic and pelvic anatomy and of the structures involved in maintaining urinary continence and erectile function. As a result, more patients are cured of their cancers today and are satisfied with their quality of life post-prostatectomy, than ever before (394, 395).
The modern RRP evolved from a succession of anatomic dissections and modifications to historical techniques (396, 397). The legacy of the anatomic RRP which permits preservation of the neurovascular bundle with maintenance of erections for many, better sphincter preservation with improved continence rates and more effective management of the dorsal vein complex resulting in less blood loss, has paved the way for not only faster and less morbid recovery (338) but also the newer adaptions of laparoscopic and robotic forms of RRP.
In addition to having pathology and staging details reviewed together with their overall medical status, it is usual to provide candidates for RRP with detailed printed information and, as a routine, have concerns and questions addressed pre-operatively. Blood may be taken in advance to be used as needed peri-operatively as an autologous transfusion. It is standard procedure for compression stockings to be fitted immediately before surgery with intermittent calf compression applied throughout and after the operation, as part of the prophylaxis against deep venous thrombosis. Since the small risk of peri-operative mortality (usually <0.5%) is mostly due to cardiovascular/respiratory complications, some surgeons insist on having all candidates for RRP evaluated with stress testing by cardiovascular physicians.
In terms of timing, it is not uncommon for surgery to be delayed 6 weeks after TRUS biopsies to permit resolution of biopsy-induced inflammation. Patients often are concerned that a delay in treatment is deleterious to the likelihood of the surgery being curative.
Graefen et al (2005) (398) analysed data from 795 patients with clinically localized prostate cancer who underwent RRP between January 1992 and June 2000 in relation to the time from biopsy to the date of RRP as a potential prognostic factor. For a mean follow-up of 33 months (1-116 months), 25% of the patients failed on the basis of a postoperative PSA level >0.1 ng/ml. They concluded that a treatment delay in the investigated time span of a few months did not adversely affect recurrence free survival rates and recommended that patients can be reassured that they can evaluate their management options without compromising efficacy due to a delay in initiation of treatment (398). Boorjian et al (2005 (399) reviewed 3,969 consecutive patients who underwent RRP for clinically localised cancer within one year of diagnosis. They reported that the time from biopsies to surgery did not influence the probability of biochemical recurrence, even for those considered to be at high risk of biochemical recurrence. The clinical and pathological features and not the delay were the important factors for estimating risk of biochemical recurrence (399).
Most RRPs are performed under regional (epidural) or general anesthesia. Advantages of the epidural approach include diminished blood loss, decreased incidence of pulmonary embolus and improved post-operative analgesia. (400-402). If general anaesthesia is used, post-operative analgesia is usually delivered parenterally for at least 24 hours, often via patient controlled analgesia. Subsequently, oral analgesics such as NSAIDs are used as indicated.
Commonly, a Pfannenstiel or a midline incision is made from the umbilicus to the pubis and continued through to the space of Retzius. The peritoneum is mobilized superiorly, enabling the surgery to be undertaken extraperitoneally. A lymphadenectomy is performed, if indicated (see below). The principles and techniques of the anatomic RRP (393) constitute the basis for the operative procedure with various modifications such as bladder neck preservation having been incorporated and used by some urologists. The entire operation is performed under complete visualization with meticulous dissection in a relatively bloodless field, to facilitate optimal cancer control, maximize post-operative continence and, if nerve-sparing is attempted, retain potency. When the specimen is removed, it is examined intraoperatively to ensure completeness of the resection and exclude any evidence of grossly positive margins or violation of the prostatic capsule. An indwelling urethral catheter is left for 1-2 weeks to maximize optimal healing of the vesicourethral anastomosis. A drain is placed near the anastomosis site: it is usually left in position for several days.
Sexual function is important in middle aged and older men (403,404) as well as their partners. Helgason et al (1996) (403) reported physiological potency for 435 randomly selected Swedish men aged 50-59, 60-69 and 70-80 years to be 97%, 76% and 51%, respectively. Blanker et al (2001) (404) confirmed this finding in data collected from 1688 men with the prevalence of significant dysfunction ranging from 3% in 50-54 year olds to 26% in males between 70-78 years. Consequently, it is not surprising that potency problems rate highly as an important consideration not only in deciding whether or not to proceed to active treatment but in determining which treatment to pursue. The importance of sexual function as a consideration is illustrated by Singer et al (2001)(405) who reported that men undergoing treatment for prostate cancer were willing to exchange an approximate 20% chance of being cured of their cancers for an increased prospect of remaining potent after treatment (405).
Consequently for many patients, the emphasis of RRP is no longer focused solely on cancer control, but extends to include lifestyle issues (394, 395, 406,407). This is not a dissimilar paradigm shift to that which has occurred with breast cancer treatment, as sexuality issues have taken a prominent role influencing treatment decisions with radical and partial mastectomies replaced by combination lumpectomy and adjuvant therapy.
Potency and continence rates associated with nerve-sparing surgery vary among surgeons and academic centres (see Table 9). It is fair to say that a degree of scepticism is expressed regarding some of the claims made in respect to post-operative potency, in particular. However, explanations for inconsistencies in cited results include differences in surgical skill, patient selection and outcome measurement methodology. Among these, patient selection ranks particularly highly. Nonetheless, it is undisputed that increasing numbers of patients are sexually potent after surgery, albeit with the use of the phosphodiesterase inhibiting drugs (Viagra™, Cialis™ and Levitra™), as a result of the modifications incorporated into the technique of anatomic nerve-sparing RRP.
Table 9. Potency rates after nerve-sparing radical prostatectomy
|
Study |
Potency Rate |
|---|---|
|
Jonler, et al (1994) (408) |
9% |
|
Fowler, et al (1993) (409) |
11% |
|
Heathcote, et al (1998) (410) |
12% |
|
Ojdeby, et al (1996) (411) |
14% |
|
Gaylis, et al (1998) (412) |
18% |
|
Talcott, et al (1997) (413) |
21% |
|
Sole-Balcells, et al (1992) (414) |
39% |
|
Davidson, et al (1996) (415) |
43% |
|
Ritchie, et al (1989) (416) |
45% |
|
Catalona, et al (1999) (417) |
67% |
|
Quinlan, et al (1991) (418) |
68% |
|
Leandri, et al (1992) (419) |
71% |
|
Noh, et al (2005) (420) |
72% |
|
Walsh, (2000) (421) |
86% |
Although definitions for above parameters vary, quality of life studies indicate that the majority of patients are satisfied with the outcomes of their surgery (394, 395, 406, 407). Link et al (2005) (422) reported their experience with laparoscopic RRP using the validated EPIC and a 5-item International Index of Erectile Function questionnaires; 78.9% of men who were previously potent were having sexual intercourse, albeit with the use of phosphodiesterase inhibitors in most instances, 12 months following surgery. Sexual bother decreased to 64% of baseline at 3 months and did not show any significant improvement subsequently. By contrast, the sexual function sub-domain, which refects erectile performance better, decreased to a mean of 36% at 3 months but showed improvement subsequently to 51% of baseline at 6 months and 64% of baseline at 12 months. Recovery of sexual function was not significantly affected by age or pre-operative potency status, although the extent of nerve sparing was a significant predictor of outcome (422).
Normal post-prostatectomy erectile function depends upon preservation of the autonomic cavernous nerves, located within the neurovascular bundles of the penis. These nerves are located immediately posterolateral to the prostatic capsule, within the periprostatic fascia at the junction of the lateral and posterior portions of the endopelvic fascia. At this position, the lateral pelvic fascia is comprised of two layers, the levator and the prostatic fascia. The neurovascular bundles pass between these layers bilaterally and can be preserved by entering the periprostatic fascia laterally and gently and meticulously dissecting them off the prostatic fascia.
If both neurovascular bundles are preserved, potency (defined as the ability to sustain sufficient erections for sexual intercourse without any aids other than phosphodiesterase inhibitors) can be as high as 68- 86% (338, 417). When only one bundle is saved, potency rates diminish substantially (423). Given the importance of sexual function to many men with prostate cancer and the differences when only one bundle is spared instead of two, it is common practice for every effort to be made to preserve both neurovascular bundles whenever possible, as long as the potential of cure is not considered to be jeopardized – consistent with the wishes of the patient.
The neurovascular bundles are mostly located outside of the prostatic capsule so, unless dissection violates the capsule, nerve-sparing radical prostatectomy should not compromise surgical cancer control if the tumour is organ-confined. Epstein et al followed patients with positive surgical margins present only in the posterolateral region and determined that post-prostatectomy relapse was uncommon (424). In this study, of 507 men with cT1 and cT2 tumours, the most common sites of positive margins were distal (22%), posterior (17%), and posterolateral (14%). Rosen confirmed these findings in 144 men undergoing radical prostatectomy (425). They demonstrated that, when positive margins were present, <10% had involvement in the region of the neurovascular bundles. Hence, in cases of extraprostatic extension, involvement of the posterolateral margin is less common than for other locations.
Epstein also examined paired specimens from men with prostate tumors highly suspicious for posterolateral involvement who underwent nerve-sparing prostatectomy followed by excision of the neurovascular bundles on the suspect side (423). Cancer was found in the bundles in only 17.5% of the men. In men with clinically-suspicious but pathologically negative posterolateral margins, no tumour was found in the resected bundles.
In order to attempt to maximise preservation of the neurovascular bundles, technical modifications to RRP have been reported; many of these involve methods which improve visualisaton of the neurovascular bundles (420, 426, 427, 428). The potential problem of impotence, when preservation of the neurovascular bundle is not considered appropriate, has been addressed by sural nerve grafting, employing techniques established in the management of facial and peripheral nerve injuries (429, 430). Although this approach has met with a mixed reception by urologists, claimed success rates vary with one study having reported return of erectile activity in 75% of men with maximum return of function 14-18 months post-RRP (431). However, most Urologists cite much lower success rates.
As expected, the recently introduced techniques of laparoscopic and robotic prostatectomy differ from open radical prostatectomy in that they have incorporated some adaptations for practical reasons. However, the principles of the prostatic cancer surgery remain the same and results to date are comparable (426, 432).
Keyhole approaches are attractive to patients because of perceptions of reduced surgical trauma and morbidity with, by extrapolation, less post-operative pain - even though this is uncommonly problematic with the open approach. A recently reported prospective study of robot assisted laparoscopic prostatectomy (n = 159) is illustrative in that it did not provide a clinically meaningful decrease in post-operative pain compared with RRP (n = 154), which the authors ascribed primarily to the low pain scores reported in both groups. They concluded that outcomes other than pain will ultimately determine the role of laparoscopic radical prostatectomy and Robot assisted laparoscopic prostatectomy (433).
Conceptually, better vision is afforded the surgeon with forms of endoscopic surgery to permit easier identification of structures, particularly apically (434, 435), but there is the potential problem of delay if (the infrequent) conversion to an open procedure is required in the event of bleeding. Unlike laparoscopic surgery, robotically-performed procedures involve hand-eye coordination and hand positions which are more akin to those used in open surgery; in addition, the learning period appears to be shorter (436). Although the capital costs associated with robotic surgery are, at present, very large, these are likely to decrease with time.
Following bone, the pelvic lymph nodes are the second most common site of prostate cancer metastases (437). While radionuclide bone scans provide a sensitive method for evaluating skeletal lesions, the sensitivity of CT scans to delineate lymph node metastases is poor (48, 49, 438). Pelvic lymphadenectomy prior to RRP to detect metastatic lymphatic involvement is limited to patients at high risk for tumour cell dissemination, then only proceeding to RRP if the lymph nodes are free of tumour.
In the PSA-era of the past 15 years, the rate of positive lymph nodes in patients undergoing RRP has plummeted from approximately 25-30% to under 5% (439-442). Consequently, there has been considerable debate regarding which patients should have lymph node dissections. It is generally accepted that men with Gleason scores < 7 and PSA values <10 ng/ml do not require pelvic lymphadenectomy (424). Some investigators have increased these limits to include PSA values from 10-20 ng/ml and Gleason 7 tumours (443).
The presence of a positive lymph node is a predictor of post-operative recurrence. Most studies demonstrate that such foci of cancer herald subsequent curative treatment failure: 10-year biochemical disease-free survival rates are low (361, 444). In a study designed to determine if early versus delayed hormonal ablation therapy in men with lymph node positive disease was advantageous, Messing et al (1999) (445) reported on 51 men with lymph node positive disease who were randomized to delayed therapy. At an average follow-up of 7 years, 16 percent had no biochemical or clinical evidence of disease and were never started on androgen ablation (445).
Pelvic lymphadenopathy can be performed as a separate procedure through a "mini-laparotomy" or by laparoscopy, or can be combined with RRP (446). All nodal tissue medial to the external iliac artery, from the junction of the external iliac and hypogastric arteries to the obturator foramen is removed with this procedure. It is then sent for frozen section histologic analysis. If lymphadenectomy is performed prior to a planned RRP and the frozen section report indicates that there is no cancer evident, it is usual to proceed with the prostatectomy. If there are tumour cells present in the specimen, the planned RRP is almost always aborted.
Complications of pelvic lymphadenectomy are infrequent (415, 447-450). Injury to the obturator nerve can occur in 1% of patients causing an inability to adduct the thigh. If complete transection occurs, primary anastomosis can be performed. Bleeding from obturator and iliac vessels is uncommon as are ureteric injuries. A lymphocele may form in the pelvis which can become symptomatic and require sclerosis or formal drainage into the peritoneal cavity. (451).