Материал: Oxford American Handbook of Urology ( PDFDrive )
82 CHAPTER 3 Bladder outlet obstruction
Medical management of BPH: alternative drug therapy
Anticholinergics
For a man with frequency, urgency, and urge incontinence—symptoms suggestive of an overactive bladder—consider prescribing an anticholinergic (e.g., oxybutynin, tolterodine, trospium chloride, or flavoxate). There is the concern that these drugs could precipitate urinary retention in men with BOO (because they block parasympathetic/cholinergic mediated contraction of the detrusor), but the risk of this occurring is probably very low, even in men with urodynamically proven BOO.1
Phytotherapy
An alternative drug treatment for BPH symptoms, and one that is widely used in Europe and increasingly in North America, is phytotherapy. Half of all medications consumed for BPH symptoms are phytotherapeutic ones.2 These agents are derived from plants and include the African plum (Pygeum africanum), purple coneflower (Echinacea purpurea), South African star grass (Hipoxis rooperi), and saw palmetto berry (Seronoa Repens, Permixon).
Saw palmetto contains an anti-inflammatory, antiproliferative, estrogenic drug with 5A-reductase inhibitory activity, derived from the American dwarf palm. It has been compared with finasteride in a large double-blind, randomized trial, and equivalent (40%) reductions in symptom score were found with both agents over a 6-month period. A meta-analysis of 18 randomized controlled trials of almost 3000 men has suggested that Seronoa repens produces similar improvements in symptoms and flow rates to those produced by finasteride.3
A recent New England Journal of Medicine study found saw palmetto no better than placebo in relieving BPH symptoms.4
South African star grass (Hipoxis rooperi, marketed as Harzol) contains B-sitosterol, which may induce apoptosis in prostate stromal cells by causing elevated levels of TGF-B1. In a double-blind, randomized control trial, symptom improvement was 5 points over that with placebo.
For other agents (e.g., Urtica dioica—stinging nettle; the African plum) the studies have not been placebo controlled and lack sufficient statistical power to prove conclusively that they work.2
1 Reynard J (2004). Does anticholinergic medication have a role for men with lower urinary tract symptoms/benign prostatic hyperplasia either alone or in combination with other agents? Curr Opin Urol 14:13–16.
2 Lowe FC, Fagelman E (1999). Phytotherapy in the treatment of benign prostatic hyperplasia: an update. Urology 53:671–678.
3 Wilt JW, Ishani A, Stark G, et al. (1998). Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review. JAMA 280:1604–1608.
4 Bent S, et al. (2006) Saw palmetto extracts for treatment of benign prostatic hyperplasia. N Engl J Med 354:557–566.
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84 CHAPTER 3 Bladder outlet obstruction
Minimally invasive management of BPH: surgical alternatives to TURP
In 1989, Roos reported a seemingly higher mortality and reoperation rate after TURP than with open prostatectomy.1 This result, combined with other studies suggesting that symptomatic outcome after TURP was poor in a substantial proportion of patients and that TURP was associated with substantial morbidity, prompted the search for less invasive treatments.
The two broad categories of alternative surgical techniques are minimally invasive and invasive. All are essentially heat treatments, delivered at variable temperature and power and producing variable degrees of coagulative necrosis of the prostate or vaporization of prostatic tissue.
Transurethral radiofrequency needle ablation (TUNA) of the prostate
Low-level radiofrequency is transmitted to the prostate via a transurethral needle delivery system, the needles that transmit the energy being deployed in the prostatic urethra once the instrument has been advanced into the prostatic urethra. It is done under local anesthetic, with or without intravenous sedation. The resultant heat causes localized necrosis of the prostate.
Improvements in symptom score and flow rate are modest. Side effects include bleeding (one-third of patients), UTI (10%), and urethral stricture (2%). No adverse effects on sexual function have been reported.2
The UK National Institute for Clinical Excellence3 and the AUA Guidelines Committee4 have endorsed TUNA as a minimally invasive treatment option for symptoms associated with prostatic enlargement. Concerns remain with regard to long-term effectiveness and retreatment rates.
Transurethral microwave thermotherapy (TUMT)
Microwave energy can be delivered to the prostate via an intraurethral catheter (high-energy system with a cooling system to prevent damage to the adjacent urethra or a low-energy system without a cooling mechanism), producing prostatic heating and coagulative necrosis. Subsequent shrinkage of the prostate and thermal damage to adrenergic neurons (i.e., heat-induced adrenergic nerve block) relieve obstruction and symptoms.
1 Roos NP, Wennberg J, Malenka DJ, et al. (1989). Mortality and reoperation after open and transurethral resection of the prostate for benign prostatic hyperplasia. N Engl J Med 320:1120–1124.
2 Fitzpatrick JM, Mebust WK (2002). Minimally invasive and endoscopic management of benign prostatic hyperplasia. In Walsh PC, Retik AB, Vaughan ED, Wein AJ (Eds.), Campbell’s Urology, 8th ed. Philadelphia: Saunders.
3 Transurethral radiofrequency needle ablation of the prostate. National Institute for Clinical Excellence Interventional Procedure Guidance, October 2003.
4 AUA Clinical Guidelines: Management of BPH (2003; updated 2006). http://www.auanet.org/ content/guidelines-and-quality-care/clinical-guidelines.cfm?sub=bph
MINIMALLY INVASIVE MANAGEMENT OF BPH 85
Many reports of TUMT treatment are open studies, with all patients receiving treatment (no “sham” treatment group where the microwave catheter is inserted, but no microwave energy is given—this results in 10-point symptom improvement in approximately 75% of men). Compared with TURP, TUMT results in symptom improvement in 55% of men and TURP in 75%. Sexual side effects after TUMT (e.g., impotence, retrograde ejaculation) are less frequent than after TURP, but the catheterization period is longer, and UTI and irritative urinary symptoms are more common.5
The American Urological Association (AUA) and European Association of Urology (EUA) guidelines state that TUMT “should be reserved for patients who prefer to avoid surgery or who no longer respond favorably to medication.”
High-intensity focused ultrasound (HIFU)
A focused ultrasound beam can be used to induce a rise in temperature in the prostate or, indeed, in any other tissue to which it is applied. For HIFU treatment of the prostate, a transrectal probe is used. A general anesthetic or heavy intravenous sedation is required during the treatment. It is regarded as an investigational therapy.
5 D’Ancona FCH, Francisca EAE, Witjes WPJ, et al. (1998). Transurethral resection of the prostate vs high-energy thermotherapy of the prostate in patients with benign prostatic hyperplasia: longterm results. Br J Urol 81:259–264.
86 CHAPTER 3 Bladder outlet obstruction
Invasive surgical alternatives to TURP
Transurethral electrovaporization of the prostate (TUVP)
TUVP vaporizes and dessicates the prostate. TUVP seems to be as effective as TURP for symptom control and relief of BOO, with durable (5-year) results. Operating time and inpatient hospital stay are equivalent. Requirement for blood transfusion may be slightly less after TUVP.
TUVP does not provide tissue for histological examination, so prostate cancers cannot be detected. The AUA guidelines have endorsed TUVP as a surgical treatment option for prostatic symptoms.1
Laser prostatectomy
Several different techniques of laser prostatectomy evolved during the 1990s.
Transurethral ultrasound-guided laser-induced prostatectomy (TULIP)
This is performed using a probe consisting of a Nd:YAG laser adjacent to an ultrasound transducer. This is currently not used.
Visual laser ablation of the prostate (VLAP)
This side-firing system used a mirror to reflect or a prism to refract the laser energy at various angles (usually 90°) from a laser fiber located in the prostatic urethra onto the surface of the prostate. The principle tissue effect was one of coagulation with subsequent necrosis.
Contact laser prostatectomy
This technique produces a greater degree of vaporization than with VLAP, allowing the immediate removal of tissue.
Interstitial laser prostatectomy (ILP)
ILP is performed by transurethral placement of a laser fiber directly into the prostate, which produces a zone of coagulative necrosis some distance from the prostatic urethra.
TULIP, VLAP, contact laser prostatectomy, and ILP have been succeeded by holmium laser prostatectomy.
Holmium laser prostatectomy
The wavelength of the holmium:YAG laser is such that it is strongly absorbed by water within prostatic tissue. It produces vaporization at the tip of the laser fiber. Its depth of penetration is <0.5 mm, thus it can be used to produce precise incisions in tissue. When the beam is de-focused, it provides excellent hemostasis.
This method can be used with normal saline, thus avoiding the possibility of TURP syndrome.
Three techniques of Holmium laser prostatectomy have been developed in progression:
•Vaporization (holmium-only laser ablation of the prostate, HoLAP), which is time consuming and suitable only for small prostates
•Resection (holmium laser resection of the prostate, HoLRP), which has a similar symptomatic outcome to that of TURP.