diagnosed cancer

Adenocarcinoma of the prostate is the most commonly diagnosed cancer and the second leading cause of death in American males. The recent surge in the incidence of prostate cancer is most likely due to the use of the serum prostate-specific antigen (PSA) test, which has also changed trends in clinical and pathologic features of prostate cancer. PSA testing offers earlier detection, meaning that patients with known prostate cancer are increasingly younger and have earlier-stage, clinically localized disease. As a result, more patients have potentially curable lesions and can benefit from radical prostatectomy.

Recently, the use of minimally invasive radical prostatectomy, particularly robotic prostatectomy, has surged. These new approaches provide excellent visualization of the anatomy and have resulted in less pain and earlier discharge, with equivalent oncologic efficacy. However, even in this era, a sound and fundamental knowledge of traditional open radical prostatectomy, with and without nerve-sparing, is crucial to the urologist's armamentarium.

History of the Procedure

In 1947, Millin introduced the retropubic approach to prostatectomy. The operation had distinct advantages overperineal prostatectomy in that (1) urologists were more familiar with the retropubic anatomy and that (2) the retropubic approach permits the ability to perform an extraperitoneal pelvic lymph node dissection for staging purposes.

During the past decade, modifications in the technique of radical retropubic prostatectomy and the introduction of the anatomic nerve-sparing method have dramatically decreased the frequency of the most concerning associated morbidities—incontinence and impotence.

Walsh deserves much credit for pioneering the technique of nerve-sparing radical retropubic prostatectomy.¹ Prior to anatomic characterization in the early 1980s and the description and anatomic characterization of the Santorini plexus, the operation was fraught with massive blood loss and morbidity.

Problem

Prostate cancer is the second most common malignancy in males after cutaneous malignancies and is the second most common cause of cancer death among men in the United States. Prostate cancer is predominantly a disease of elderly men, and the absolute number of cases is expected to increase as worldwide life expectancy increases.

Frequency

Each day in the United States, more than 100 men die of prostate cancer. According to American Cancer Society (ACS) estimates, in 2007, 218,890 men will be newly diagnosed with prostate cancer and 27,050 men will die from the disease.²

The incidence of prostate cancer varies throughout the world but is generally higher in Western developed countries. To illustrate, African American men (in whom the incidence of prostate cancer is highest) are 200 times as likely to develop prostate cancer as are Chinese men living in Asia, in whom the incidence of prostate cancer is among the lowest in the world.

Migration studies have revealed increased prostate cancer rates among migrants who move from areas with low prevalence to areas of high prevalence. In one study, the incidence of prostate cancer in emigrants from Japan increased 4-9 times over the incidence in Japan.³

Etiology

Migration studies suggest that environmental factors (eg, diet) play an important role in prostate cancer (seeProstate Cancer: Nutrition). Researchers have found a positive correlation between higher fat consumption, especially animal fat, and a higher prostate-cancer death rate. Higher fat consumption can increase the relative risk by a factor of 1.6-1.9.

Experts suggest certain dietary habits to lower the risk of prostate cancer. These include a low-fat, high-fiber diet, which lowers serum androgen levels. Researchers have investigated other dietary factors, including selenium, lycopene, vitamin D, alpha-tocopherol, vitamin E, and large amounts of green tea and have postulated that these factors may prevent prostate cancer.

Family history and genetics are important in the etiology of prostate cancer. Having a single first-degree relative with prostate cancer increases the prostate-cancer risk by a factor of 2.1-2.8. Having both a first-degree and a second-degree relative with prostate cancer increases the risk by a factor of 6. Familial predisposition can be due to common environmental exposures; recently, however, researchers mapped a potential major prostate cancer susceptibility locus (1q24-25). This gene, called HPC1, is involved in 33% of hereditary prostate-cancer cases.

Men with a family history of female breast cancer are also at an increased risk of prostate cancer. Specific mutations of BRCA1 and BRCA2, 2 genes involved in familial breast cancers, appear to confer an increased risk for prostate cancer.

Presentation

Before the advent of PSA testing, more cases of prostate cancer were detected at a more advanced stage. Today, most prostate cancers are detected with PSA testing, which has resulted in more cases of prostate cancer being detected earlier, at a lower stage, and organ-confined.

Over the past 10 years, the number of radical prostatectomies performed for clinically localized prostate cancer has risen. Most of this increase is due to the higher number of surgeries performed for c-T1c disease.

The detection of organ-confined prostate cancer has increased through PSA-based screening of asymptomatic men; most tumors detected have clinical and pathologic features of clinically important prostate cancer.

Indications

urrently, nerve-sparing radical retropubic prostatectomy remains a reasonable treatment option for men with clinically localized prostate cancer who have at least a 10-year life expectancy and low comorbidities. It is a well-tolerated procedure that is associated with low morbidity. The procedure is not limited to men younger than a certain age, but the authors generally do not consider patients older than 73 years for prostatectomy. The authors believe that cases have to be judged on an individual basis, but, in an elderly patient with prostate cancer who has alternatives to major surgery and in whom a 10-year overall survival is improbable, justifying a major operation is difficult.

Although the optimal management of higher-stage disease is controversial, radical prostatectomy remains a viable treatment option in T3 disease for select patients. In patients with poorly differentiated disease, surgery can be supplemented with adjuvant hormonal therapy because monotherapy, in any form, is fraught with failure (seeProstate Cancer: Neoadjuvant Androgen Deprivation). Amling et al (1998) reported the Mayo Clinic experience with radical prostatectomy in clinical T3 disease.⁴ Some cases of prostate cancer are clinically overstaged and can be cured with surgery alone.

Relevant Anatomy

Physicians must have a clear understanding of the anatomy pertinent to radical prostatectomy. The understanding of periprostatic anatomy, achievement of vascular control, and preservation of the neurovascular bundles allow a safe and anatomic approach to the operation, with reduced morbidity.

• The fascial investment of the bladder and the prostate, the endopelvic fascia (ie, pelvic fascia), sweeps down and off the pelvic sidewall, where it covers the levator ani muscle.
• The puboprostatic ligaments represent the anterior condensation of the fusion of the parietal and visceral pelvic fascia.
• Incising the fascia at this point of fusion exposes the lateral surface of the prostate and the anterolateral rectal wall. At this point, the lateral periprostatic or lateral prostatic fascia becomes evident. This layer continues posteriorly to cover the neurovascular bundles and to become the lateral rectal fascia, and it continues distally over the membranous urethra to become the lateral periurethral fascia.
• The lateral periprostatic fascia is continuous with the endopelvic fascia and is fused to the anterior and posterior Denonvilliers fascia. The rectal fascia (ie, posterior Denonvilliers fascia) covers the anterior surface of the rectum. The neurovascular bundles are invested in this posterior layer of Denonvilliers fascia laterally and are posterior and lateral to the prostate.
• Anterior and posterior leaflets of the anterior Denonvilliers fascia envelop the seminal vesicles. Entering the posterior aspect of the anterior Denonvilliers fascia is essential for the complete dissection of the seminal vesicles in radical retropubic prostatectomy for localized prostate cancer.
• The prostatic plexus of veins (ie, Santorini plexus) carries the venous return from the deep dorsal vein of the penis and the cavernosal veins. These venous effluents ultimately drain into the internal iliac veins.
• The venous drainage may vary greatly and may be asymmetric. Take care in the dissection, especially at the prostate apex, where blood loss could be massive. The superficial branch lies within the retropubic fat, between the puboprostatic ligaments.
• The periphery of the glandular elements of the prostatic peripheral zone contains a fibromuscular rim referred to as the prostatic capsule. The base or apex of the prostate has no well-defined capsule. Here, the capsule is deficient as it merges with the smooth muscle of the bladder neck and with the striated muscle of the urethral sphincter.
• The striated urethral sphincter is directly beneath the dorsal venous complex. This sphincter is well-developed anterolaterally, creating a horseshoe-shaped appearance. Because the striated sphincter mechanism lies directly beneath the dorsal venous complex, take care not to damage its fibers during vein control.
• The cavernous nerves originate from the pelvic plexus on either side of the rectum. They travel posterolaterally to the prostate beneath the cover of the lateral periprostatic fascia. At the level of the membranous urethra, these nerves course anteriorly and lie directly lateral to the urethra. Branches of the nerves are located anteriorly close to the vessels of the penile hilum at the base of the membranous urethra, where the striated sphincter ends.
• Recent experience with robotic and laparoscopic radical prostatectomy has led to the identification and characterization of the vesicoprostatic muscle. This retrotrigonal layer marks the posterior limit of dissection lying anterior to the ejaculatory organs. This layer corresponds with the posterior longitudinal fascia of the detrusor muscle and is divided after the division of the bladder neck posteriorly, just before encountering the ampullae of the vas deferens. The description of this layer challenges the once-common belief that this is actually a layer of the anterior Denonvilliers fascia.

Contraindications

All patients selected for nerve-sparing radical retropubic prostatectomy should have low comorbidities, at least a 10-year life expectancy, and clinically localized disease. Patients with locally advanced disease cannot undergo the nerve-sparing operation; because of the extent of the local tumor burden (especially posteriorly), the nerve-sparing procedure can compromise the adequacy of the operation.

Whether patients with preoperative erectile dysfunction can benefit from nerve-sparing procedures in the sildenafil era has not been extensively studied. Therefore, the authors still do not recommend the nerve-sparing approach in patients with preoperative erectile dysfunction.

The nerve-sparing operation should not be attempted to treat locally advanced prostate cancer. In that setting, the radical prostatectomy specimen should include both layers of Denonvilliers fascia, with a wide excision of the lateral pelvic fascia and the neurovascular bundles en bloc with the prostate and ejaculatory organs.

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