THERMOCOAGULATION EFFECT OF DIODE-LASER RADIATION IN THE HUMAN PROSTATE - ACUTE AND CHRONIC STUDY

Objectives, To evaluate the safety and efficacy of low-power slow-heat ing diode laser-induced photocoagulation of prostatic tissue for treat ment of benign prostatic hyperplasia, we conducted a series of acute a nd chronic studies using a diode laser (810 nm) to irradiate human pro state. Methods, The study included 6 patients undergoing radical prost atectomy because of malignancy. Laser radiation to the prostate was gi ven transurethrally, in a noncontact mode, at the time of the procedur e in 2 patients (acute group): 10 W for 300 seconds on the right side of the prostate and 15 W for 180 seconds on the left. In the remaining 4 patients (chronic group), laser radiation was given at 1, 7, 10, an d 12 weeks prior to the prostatectomy. Results, In the acute group the average depth of coagulation was 8.5 and 9.0 mm for the laser regimen s of 15 W for 180 seconds and the 10 W for 300 seconds, respectively. In the chronic group, the average depth of coagulation was 8.9 mm for both laser regimens studied. In the acute group, there was an ill-defi ned hemorrhagic ring at the periphery of the lesion. At 1 week, an int act necrotic coagulum was present. At 7 weeks, some of the coagulated tissue had already sloughed off. Longer follow-up at 10 and 12 weeks d emonstrated formation of a well-defined cavity with mostly re-epitheli alized surface. Conclusions, Our findings suggest that noncontact diod e laser (810 nm) irradiation can induce in the human prostate signific ant coagulation necrosis followed by sloughing of tissue and cavitatio n of the prostatic urethra.