KTP laser shows good results in BPH at 4 years

May 1, 2008

Treatment of lower urinary tract symptoms using an 80-watt laser prostatectomy system showed a significant decrease in IPSS and post-void residual urine, among other positive indicators.

Cancun, Mexico-Treatment of lower urinary tract symptoms using an 80-watt laser prostatectomy system showed a significant decrease in International Prostate Symptom Score (IPSS) and post-void residual urine, among other positive indicators, Swiss researchers reported at the World Congress of Endourology here.

There are many different types of laser prostatectomy, but the most widely used to date has been the potassium-titanyl-phosphate (KTP) prostatectomy (GreenLight Laser Therapy, American Medical Systems, Minnetonka, MN). The technology has been in use for a number of years, but few truly long-term studies have been done to determine whether this technique will measure up to the excellent success of standard electrosurgical transurethral resection of the prostate.

A number of studies presented at the WCE attempted to address this issue. One study from the University Hospital Basel in Switzerland involved 500 consecutive patients with LUTS secondary to BPH who were treated with KTP laser prostatectomy using the 80-watt system.

Patients remained in the hospital overnight to determine their ability to void adequately, with reinsertion of a urethral catheter in the event of urinary retention.

The results showed a significant decrease in IPSS scores and post-void residual urine, with a significant increase in peak urinary flow rate post-procedure, the effects of which appeared durable in the patients followed out to 4 years, reported Robin Ruszat, MD, consultant urologist at the University Hospital Basel. There were no episodes of transurethral resection syndrome. Fifteen patients (3%) experienced bleeding during the procedure that was significant enough to require coagulation using standard electrosurgical transurethral methods.

Post-procedure, 49 patients (9.8%) had hematuria significant enough to require irrigation, with two patients (0.4%) requiring a blood transfusion. The re-catheterization rate post-procedure was 11.2%. The re-operation rate, either with TURP or repeat KTP prostatectomy, was 6.8% at a mean of 24.9 months. The bladder neck and urethral stricture rates were noted at 3.2% and 5.8%, respectively.

Incidence of dysuria questioned

The paper sparked much discussion at the session. One issue raised was the average total energy used during each procedure, especially important because a high-performance, 120-watt version of the KTP system is now available. The incidence of dysuria post-procedure lasting usually for 6 to 8 weeks was noted at 12.4%, slightly higher than that generally associated with standard TURP, and the question was raised as to whether the use of higher energies would help prevent this. This led one audience member to ask exactly how one determined that the procedure was completed or not, and how this would potentially affect dysuria and re-catheterization rates.

Dr. Ruszat said he agreed that the use of the higher-power system might indeed improve the outcome parameters mentioned due to the possibility of removing the obstructive tissue faster and more completely. Particularly in large prostate glands, University Hospital urologists were not able to reach the capsule with the 80-watt device, he noted.

"The end of the procedure was determined by surgeon opinion of large, good, visible prostatic cavity," he said.

"Most of the patients with pronounced dysuria after the procedure complained primarily about irritative micturition symptoms before the operation," he added. Dr. Ruszat noted that the group started using the 120-watt KTP system in April 2007, and that future data might help better explain this phenomenon.

Another point of discussion was the incidence of significant bleeding requiring standard electrosurgical transurethral techniques for control (3.0%). Dr. Ruszat said the definition of "significant bleeding" in these patients was bleeding "significant enough to compromise visibility and making the procedure more difficult." He noted that most of these occurred in anticoagulated patients and that, despite this, only two patients (0.4%) required blood transfusion.

A member of the audience asked whether those patients who required irrigation post-procedure were on warfarin, to which Dr. Ruszat responded in the affirmative. When asked what the highest international normalization ratio was and whether he would try to limit this to decrease the incidence of complications, Dr. Ruszat pointed to the fact that, overall, the incidence of complications was still low and, as such, "there were no real problems with these patients."

He pointed out that the bladder neck and urethral stricture rates decreased significantly when the treating urologists changed from a 26F resectoscope to a 22F resectoscope.

As for the 34 patients who required re-operation, Dr. Ruszat said this occurred "primarily in patients with prostates greater than 100 mL," and that subjectively there was appreciation of prostate regrowth, often in the apical area.