GreenLight Laser Effective for LUTS

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Symptoms, urine flow improved significantly.

SHANGHAI—Laser vaporization of prostate tissue using a 120-watt GreenLight laser significantly reduces lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH), according to a study conducted at nine centers in seven countries.

The GreenLight laser is not yet widely used in North America or Europe, but this improved version of the potassium-titanyl-phosphate laser is gaining a foothold on both continents. The nine centers included hospitals in New York City and Boston.

Among 629 subjects with BPH-related LUTS, prostate volume fell by 55% over an average of 7.7 months' follow-up and PSA levels dropped by 43%, according to findings presented here at the World Congress of Endourology. Symptoms decreased significantly and urine flow rose significantly. The mean American Urological Association Symptom Score decreased from 21.6 at baseline to 8.4 after six months. The mean maximum flow rate rose from 8.1 to 20.2 mL/sec.

Investigators observed a 12.1% rate of intraoperative bleeding that mainly led to impaired intraoperative visibility, a 2.5% rate of capsular perforation, and an 8.3% rate of recatheterization because of urine retention in the immediate postoperative period. In addition, for 3.1% of patients, surgeons had to switch to transurethral prostatectomy because of bleeding or technical problems.

Investigators applied between 4.1 and 5.0 kJ for each milliliter of prostate tissue ablated. Prostates ranged volume from 24 to 165 mL. The average was 65.4 mL. The mean operating time was 64.5 minutes, including 44.9 minutes of laser application.

Lead investigator Alexander Bachmann, MD, provisional head of the department of urology at  University Hospital Basel, in Switzerland, noted that patients who were receiving anticoagulation medication or have prostates too large to be eligible for transurethral prostatectomy were initially thought likely to benefit most from this approach.
“But we now use the GreenLight laser approach nearly routinely in all our patients with lower urinary tract symptoms due to prostate enlargement,” Dr. Bachmann said.

Commentary

By Carson Wong, MD, FRCSC, FACS and Reza S. Malek, MD, FRCSC, FACS

The study by Bachmann et al. provides data on a large number of 120W GreenLight HPS laser PVP-treated patients (49.5% of whom were anticoagulated) performed by a number of PVP surgeons.  The researchers presented findings from 629 prospectively studied patients who had a mean prostate volume of 65 mL (12-260) and mean PSA of 4.9 ng/mL (0.1-38.0).  A 55% prostate volume reduction was achieved at a mean follow-up of 7.7 months.  Improvements in IPSS and Qmax, and reductions in prostate volume and PSA were reported at one, three and six months post-operatively.

The clinical efficacy, as measured by IPSS and Qmax improvement, as well as reductions in PSA and prostate volume postoperatively, is impressive.  These results are echoed by Spaliviero et al.1, who reported statistically significant improvement in AUA symptom score, Qmax and prostate volume reduction one year following 120W GreenLight HPS laser PVP.  However, in Bachmann et al.'s study, approximately 50% of the study cohort was available for evaluation during the follow-up interval, with less than 20% of patient data available for IPSS and Qmax values and less than 5% of patient data available for PSA and prostate volume reduction determinations. This is likely due to the prospective nature of this study with as yet pending follow-up data and statistical analysis.

Energy utilization for prostate vaporization was relatively large in most cases:  a mean of 274755.7 J to treat a mean prostate volume of 65.4 mL.  With an approximately 50% prostate volume reduction reported one month post-surgery, the estimated volume of prostate tissue removed with that level of applied energy in such a gland was 33 mL.

Nonetheless, the short-term outcomes reported here suggest that 120W GreenLight HPS™ laser PVP is safe and effective for the treatment of lower urinary tract symptoms secondary to obstructive benign prostatic hyperplasia. Continued follow-up is required to assess medium and long-term results.

Dr. Wong is Associate Professor of Urology at the University of Oklahoma Health Sciences Center in Oklahoma City. Dr. Malek is Professor Emeritus of Urology at the Mayo Clinic in Rochester, Minn.

References

  1. Spaliviero, M, Araki, M and Wong, C.  Short-term outcomes of GreenLight HPS laser photoselective vaporization prostatectomy (PVP) for benign prostatic hyperplasia (BPH).  J Endourol.  2008; 22:2341-2347.
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