INCREASING THE THERMAL DOSE IN TRANSURETHRAL MICROWAVE THERMOTHERAPY PRODUCES NO IMPROVEMENT IN THERAPEUTIC EFFICACY

Background: Transurethral microwave thermotherapy (TUMT) is a minimally invasive treatment for benign prostatic hyperplasia (BPH). It has been reported that increased thermal dose and higher intraprostatic temperatures resulted in improved clinical response. Recently we treated BPH patients with the prostatron device using a new version of software (Prostasoft 2.5), which was intended to increase thermal delivery by allowing maximum power up to 70W. The safety and clinical results were compared between the patients treated with Prostasoft 2.5 and those treated with the currently available software (Prostasoft 2; maximum power up to 50W). Methods: A total of 105 patients were treated successively with two treatment protocols. Sixty-three patients were treated with Prostasoft 2 between September 1992 and July 1993. while 42 were treated with Prostasoft 2.5 between August 1993 and April 1994. Therefore, this investigation was a retrospective nonrandomized study. There was no significant difference in the baseline patient characteristics between the two groups. Results: Total thermal dose delivered to the prostate was significantly higher in the Prostasoft 2.5 group than that in the Prostasoft 2 group (137 kJ versus 116 kJ, P < 0.05). No serious complications were encountered in either group. Six months after TUMT, in both the Prostasoft 2.5 and Prostasoft 2 groups there was an improvement in patient condition as measured by the mean I-PSS, OOL, and peak How rate values, as well as the overall therapeutic efficacy. The two groups differed in the amount of posttreatment improvement from between 8% and 22%, but this difference was not statistically significant. Conclusions: Our study suggests that higher thermal dose attained by Prostasoft 2.5 does not necessarily result in more pronounced clinical improvement, although clinical response to TUMT has often been reported to be dependent upon thermal dose.