One hundred and seventy two patients with benign prostatic hyperplasia (BPH) were treated with transurethral microwave thermotherapy (TUMT) using Prostcare (Bruker Spectrospin). The treatment was performed with an effect of 52 W and a frequency of 915 MHz, which was generally well tolerated and no serious side effects were observed. In the majority of the patients there was an improvement of subjective symptoms with a significant decrease in Madsen and bothering scores after treatment. In the total patient group, Qmax and voided urine volume were increased slightly, but not statistically significantly. The patients were divided in responders and non-responders, based on Madsen symptom score after 3 months or if complementary treatments were necessary during the follow up period of one year. No significant differences between the groups were observed regarding pretreatment variables except that patients in the responder group experienced the treatment more painful than non-responders. Qmax in the responder group was significantly improved at 6 and 12 months follow up. PSA levels increased significantly after the treatment. Routine evaluation using flow rate, estimation of prostatic size, measurement of residual urine volume and cystoscopy does not give sufficient information for predicting treatment outcome.

High energy transurethral microwave thermotherapy using a heat shock strategy is an effective treatment for benign prostatic hyperplasia and produces a better outcome than shown with lower energy protocols. However, the morbidity is not negligible and ejaculation quality is affected. Less relative energy is needed for large than small prostate volumes to reach the same intraprostatic temperature level as demonstrated by radiometry.

Objective To compare the heat characteristics of the microwave antennae, the absorbed energy in the target volume and the cooling capacity of the catheters of three common devices for transurethral microwave thermotherapy (TUMT), i.e. the Prostcare, Prostatron and ProstaLund. Materials and methods The microwave emission from the respective catheters or antennae was measured in a tissue‐equivalent ‘phantom’ prostate. From these measurements the distribution of absorbed energy from the respective catheters and antennae was calculated from the characteristics of the phantom, the absorbed energy and the temperature difference before and after heating. The cooling capacity of the different catheters were measured by submerging each catheter in a thermally isolated water bath at a known temperature and determining the cooling of the water bath caused by the catheter. Results The design of the microwave antenna influenced the heating profile significantly. The energy absorbed by the prostate model varied among the devices, but was between 13 and 21% of the stated applied energy. The cooling capacity also varied, being least in the Prostcare and greatest in the ProstaLund catheters. Conclusions Users of TUMT should be aware of possible back‐heating along the catheter, as this limits the microwave power that can be used safely. Furthermore, the ‘treatment energy’, which is commonly used as an indicator to describe the intensity of TUMT treatments, is ambiguous and not stringent, in that the microwave energy absorbed in the prostate is only a small fraction of this value.

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