Endoscopic laser ablation of the prostate (ELAP): changes in magnetic resonance imaging and clinical outcome at 1 year

Abstract

Objective To assess the ability of magnetic resonance imaging (MRI) to detect tissue changes immediately after laser ablation of the prostate and to correlate these changes with clinical outcome by detecting changes that may improve the outcome by allowing the laser dosimetry to be adjusted during therapy by monitoring effects on gland morphology. Patients and methods Eight men with proven bladder outlet obstruction had a standard four‐quadrant laser ablation of the prostate with a side‐firing non‐contact fibre. MRI scans were performed before, during and immediately after treatment and again after one week, 3 months and one year. Results The clinical outcome was a decrease in the American Urological Association (AUA)‐7 symptom score from a pre‐operative mean of 21.3–12.0 1 year after treatment and a corresponding increase in peak urinary flow rates from a mean of 8.9 mL/s to 12.3 mL/s. Immediately after treatment, MRI showed marked swelling of the gland (mean increase in volume 34%, range 12–75) with the loss of internal architecture. A low‐signal thin periurethral band was present in six of the eight patients after 1 week and was replaced by a wider periurethral ring at 3 months in four of the six patients. No patient had evidence of prostatic cavitation after treatment or a significant reduction in prostate volume at 1 year. Conclusion MRI can detect tissue changes after laser ablation of the prostate. The marked swelling seen on MRI immediately after laser prostatectomy may explain the delayed improvement in symptoms. The periurethral ring may indicate the depth to which laser energy has an effect on the tissue and could delineate an area of necrosis. The lack of cavitation at one year questions the durability of the effect of laser treatment delivered in this way.

The use of lasers in benign prostatic enlargement

“…Adding a bladder neck incision (prostatotomy) seems to help [26•]. Magnetic resonance studies immediately following VLAP have shown a mean increase in the volume of the prostate of 34% [41], which probably causes the obstruction. It is still not clear to what degree various other factors are to blame (ie, residual obstruction, infection, the presence of a suprapubic or urethral catheter).…”