Local microwave hyperthermia as a treatment alternative for benign prostatic hyperplasia

It appears that the technology for local microwave application of heat to the prostate for the management of benign prostatic hyperplasia has arrived. There are a number of issues to be resolved in the coming years that will determine the role this modality will play in the overall management of men with benign prostatic hyperplasia. These issues include: transurethral versus transrectal route, hyperthermia (42 degrees C to 44 degrees C) versus thermotherapy (greater than 45 degrees C), and a proper assessment as to whether the technique is really efficacious, given the known placebo response in all studies currently available. The results with the transrectal route appear to improve patients' symptoms objectively and subjectively, without causing irreversible tissue effects. Thus, its action has been likened to alpha blockade. But, it appears that the transrectal approach is relatively inefficient because of a significant loss in microwave power with rectal cooling. A probe placed transurethrally can accurately and easily deliver the intended power to the center of the prostate, where theoretically it has its greatest effect on both the dynamic and static components of outlet obstruction. Currently, the transurethral devices described by Sapozink and Devonec will produce histologic necrosis. The theoretical value of combining urethral heating with cooling is that it will allow treatments of greater power deeper in the prostate adenoma, but the greatest advantage over transurethral heating without cooling may be in the ability to effect a response in a single session. Finally, the placebo response is a well known phenomenon seen in all drug trials conducted for the management of benign prostatic hyperplasia.(ABSTRACT TRUNCATED AT 250 WORDS)