Transurethral microwaves for benign prostatic hypertrophy
ACP J Club. 1993 Sept-Oct;119:39. doi:10.7326/ACPJC-1993-119-2-039
Bdesha AS, Bunce CJ, Kelleher JP, et al. Transurethral microwave treatment for benign prostatic hypertrophy: a randomised controlled clinical trial. BMJ. 1993 May 15; 306:1293-6.
To compare transurethral microwave thermotherapy (TMT) with sham treatment in men with benign prostatic hypertrophy (BPH) for improvement in symptoms, flow rates, and reduction in residual urine volume.
Randomized, double-blind, controlled trial with 3-month follow-up.
A urology clinic in a British hospital.
42 men (mean age 63 y) who were candidates for prostatectomy (symptoms for > 6 mo), had scores > 14 on a symptom score questionnaire (daytime frequency, nocturia, force of stream, hesitancy, terminal dribble, urgency, dysuria, and intermittent and incomplete voiding), and had a residual urine volume ≥ 50 mL and ≤ 200 mL, or a peak flow rate < 15 mL/s. Exclusion criteria were prostatic malignancy, impaired renal function, prostatic urethra > 40 mm, large obstructing middle lobes, coexisting urinary tract disease, or previous prostate surgery. Follow-up was 95%.
All patients had a full clinical examination, were catheterized, and had the urethra anesthesized with topical lignocaine gel. 22 patients were randomized to receive a single, 90-minute TMT session using a LEO Microthermer (Laser Electro Optics) that delivered a variable power output with a maximum of 20 W at 915 MHz. 18 men were randomized to receive a similar sham treatment. Abdominal heating pads were used to aid blinding.
Main outcome measures
Residual urine volumes by ultrasonography; urine flow rates using the mean of 2 voidings; and side effects, sexual performance, and symptom scores by questionnaire, all assessed at 3 months. Assessors were blinded.
After 3 months, patients who received TMT, compared with patients who received the sham treatment, had better total symptom scores (-19 for TMT vs. -5 for sham; P < 0.001); decreased daytime frequency (-3.9 vs. 0.0; P < 0.002) and nocturia (-1.6 vs. -0.2; P < 0.01); and improvements in force of stream (-1.6 vs. 0.0; P < 0.001), terminal dribble (-2.8 vs. -0.3; P < 0.02), urgency (-2.9 vs. -0.9; P < 0.05), and residual urine volume (-52 vs. +14 mL; P < 0.05). A nonsignificant trend toward improved peak urine flow was noted (+2.3 vs. -1.0 mL/s). Side effects were minimal, and all patients remained capable of antegrade ejaculation.
Men with benign prostatic hypertrophy who were treated with transurethral microwave thermotherapy had reduced residual urine volumes compared with men who were given a sham treatment.
Source of funding: Not stated.
For article reprint: Mr. R.O. Witherow, Department of Urology, St. Mary's Hospital, London, United Kingdom W21NY. FAX 44-71-637-5373.
Bdesha and colleagues have executed a small, well-designed study of transurethral "thermal therapy," a new treatment for BPH. Unlike earlier "hyperthermia" devices that heated the prostate less and required multiple treatments, this device is designed to sufficiently heat the prostate to cause coagulation necrosis in a single treatment.
In the past, device therapies were often evaluated less rigorously than drugs; the investigators are to be congratulated for the use of sham procedure controls similar to the trial by Ogden and colleagues (1). Three months later, more patients treated with thermal therapy guessed they were treated actively than did patients treated with placebo, illustrating the practical difficulties with this design.
BPH is treated to reduce symptoms and prevent complications, such as acute retention and bladder or kidney deterioration. Thermal therapy appears to accomplish the former. Nonuniformity in symptom measurement, however, confounds comparison of studies. The unreferenced symptom index used in this study does not appear to be the International Prostate Symptom Score of the World Health Organization, which rates 7 urinary symptoms (2).
Peak urine flow and residual volumes are often used as proxy evidence of physiologic improvement from BPH treatment to show reduction in long-term risk for complications from BPH. The nonsignificant improvements in peak flow were modest compared with those seen with prostatectomy, and residual volumes were initially low. The study was too small to reliably estimate complications.
Before thermal therapy can be advocated as an alternative to prostatectomy, these treatments need to be compared head-to-head in trials with adequate power to detect clinically important differences in long-term symptom relief, BPH complications, and adverse effects.
Michael J. Barry, MD
Massachusetts General Hospital Boston, Massachusetts, USA