How to select patients suitable for transurethral microwave thermotherapy: a systematic evaluation of potentially predictive variables.

OBJECTIVE

To identify clinical variables useful in predicting outcome after transurethral microwave thermotherapy (TUMT) of the prostate with Prostasoft v. 2.0.

PATIENTS AND METHODS

Thirty-eight men with symptomatic benign prostatic hyperplasia (BPH) were treated with TUMT using the Prostatron device with the low-energy (v. 2.0) software. Before and 6 months after treatment symptoms were evaluated using the Madsen-Iversen (M-I) symptom score, a clinical examination and suprapubic pressure-flow measurement, free urinary peak flow rate (Qmax) and determination of post-void residual urine volume (PVR). Bladder outlet obstruction was assessed from urodynamic pressure-flow studies using the classification of Abrams and Griffiths, the obstruction grading of Schäfer, and calculation of other published factors, e.g. the urethral resistance, an obstruction index and the detrusor adjusted mean passive urethral resistance factor (DAMPF). Categories of M-I score (total, irritative and obstructive), PVR and Qmax were investigated to determine whether any could predict the outcome after low-energy TUMT. The values after treatment and changes in Qmax, M-I score and PVR were used as efficacy variables.

RESULTS

Variables describing infravesical obstruction had predictive characteristics that may be useful in selecting patients for TUMT v. 2.0 and significantly better results were obtained in patients with a low to moderate obstruction as graded using the DAMPF classification of obstruction. The results also indicated that patients with a high irritative M-I score or a Qmax of 7-14 mL/s were those who fared best after TUMT.

CONCLUSIONS

Variables expressing the obstruction grade seem to be useful in predicting outcome after TUMT (v. 2.0). Patients with a high obstruction index are probably unsuitable for TUMT (v. 2.0).