Endoscopic ablation for benign enlargement of the prostate

Abstract

Newer techniques are no better than transurethral resection, but the evidence base is poor

The prevalence of prostatic enlargement on rectal examination reaches 50% at age 70 and directly correlates with age.¹ The age dependent prevalence of bothersome lower urinary tract symptoms, usually attributed to prostatic enlargement, has been demonstrated in population based studies in many countries, with moderate to severe symptoms being present in 27-56% of men aged 70-79 years in Scotland, France, Japan, and New Zealand.^{2 3 4 5}

Transurethral resection has been the procedure of choice for surgically treating prostatic enlargement since the 1950s. Its use peaked in the late 1980s and has declined with the introduction of medical treatment and alternative surgical techniques. Drivers of the development of alternative surgical methods include bleeding, electrolyte abnormalities, and prolonged hospital stay associated with transurethral resection. The linked systematic review by Lourenco and colleagues compares several alternative methods of creating an immediate opening in the prostatic urethral channel to the gold standard—transurethral resection of the prostate.⁶ These techniques can be broadly categorised as enucleation, resection, and laser ablation (collectively termed endoscopic ablation by Lourenco and colleagues).

In enucleation, the adenoma is shelled out from the capsule of the prostate. Intuitively, enucleation should offer the best chance of improving symptoms and flow rate because the entire adenoma is removed. Historically, enucleation was done through an abdominal incision. Today, endoscopic holmium laser enucleation of the prostate offers a minimally invasive method of enucleation; however, it is time consuming and technically challenging. In resection procedures—such as transurethral vaporesection, bipolar transurethral resection, or the gold standard (monopolar) transurethral resection—the adenoma is excised piece by piece. These procedures should be equivalent to enucleation if resection is carried down to the capsule. Laser ablation opens the prostatic urethra by evaporating the adenoma. This was originally tedious and reserved for smaller prostates. With refinements in technology—including higher energy lasers—ablation has become more efficient; it is now the most commonly performed procedure for benign prostatic enlargement in the United States, at least in part because it is associated with minimal blood loss and a shorter stay in hospital.⁷

The systematic review by Lourenco and colleagues identified 45 randomised controlled trials of different techniques for enucleation, resection, and ablation that met the inclusion criteria.⁶ All studies were moderate to poor quality and had small sample sizes. Compared with transurethral resection, none of the newer technologies produced significantly different improvements in flow rate and symptoms at one year. Follow-up was too short and complications were too rare and inconsistently reported to draw meaningful conclusions about adverse effects.

The review did not cover “office based” technologies such as microwave treatment and radiofrequency ablation of the prostate. These differ from the surgical procedures described above in that they can be done in the general practitioner’s surgery under sedation and do not create an immediate opening in the prostatic urethra; rather they produce delayed necrosis and sloughing of tissue. A systematic review that compared microwave treatment with transurethral resection found that it was less efficacious, but the quality of the data was too poor to draw significant conclusions about long term complications.⁸

In the US, procedures performed for benign prostatic enlargement have increased by 44% in the past six years, whereas transurethral resections have decreased by 5% each year.⁷ The newer procedures (primarily laser ablation and office based procedures) are replacing transurethral resection and expanding the number of patients seeking surgical treatment for benign prostatic enlargement. Yet are they, and are we, fully informed about the efficacy of such procedures relative to transurethral resection or medical treatment? Similarly, in the United Kingdom—where surgery is usually reserved for patients with urinary retention—are the indications for surgery expanding? If so, what are the health policy and economic consequences?

We should be careful about rapidly embracing new technology when it has not been properly compared with the gold standard see above. Although eager adoption of new technology fosters innovation in the biomedical industry, such innovation can progress so quickly that it outstrips our ability to measure the effectiveness of one treatment before the next is introduced. Furthermore, when so many generations of a single device are available—with each being only slightly different from the last (as in laser ablation technology and transurethral microwave thermotherapy)—how can we interpret the few studies that exist? This is why the systematic review by Lourenco and colleagues is so important—not only does it show what we do know but it also points out where evidence is lacking.⁶ Better randomised controlled trials with follow-up of up to 10 years are needed to properly assess complications and efficacy. In addition to clinical trials, population based studies of “real world” effectiveness and economic impact are crucial.

Cite this as: BMJ 2008;337:a535