Transrectal ultrasonography to predict the clinical outcome of transurethral microwave thermotherapy in patients with benign prostatic hyperplasia

Abstract

Background: This study evaluated the long-term efficacy of transurethral microwave thermotherapy (TUMT) in the treatment of benign prostatic hyperplasia (BPH), and determined whether the indices obtained with transrectal ultrasonography (TRUS) can predict the clinical response to TUMT. Method: Between November 1991 and June 1992, 43 patients with symptomatic BPH were treated with TUMT using the Prostcare device. The therapy consisted of a 1-hour treatment under topical anesthesia. The findings of uroflowmetry and AUA symptom score before treatment were compared with those obtained at each visit after the therapy. As the indices, the transition zone (TZ) volume, transition zone ratio (TZ ratio = TZ volume/total prostate volume), total prostate volume, and presumed circle area ratio (PCAR) were calculated. Results: There was a significant correlation between pretreatment TZ ratio and residual urine volume (r = 0.472, P = 0.0022). The efficacy rates calculated by response criteria on the 3 point scale at 2 months, 12 months, and 30 months were 44.2%, 30.2%, and 25%, respectively. The significant prognostic factors that predicted the clinical effect 1 year after treatment were the TZ ratio and intraprostatic temperature. After controlling for the treatment temperature, the multivariate logistic regression model demonstrated that the TZ ratio was the significant predictor (P = 0.049) of 1 year efficacy of treatment. Conclusion: The present study showed that the efficacy rate of TUMT at 30 months was 25%, and that TRUS provides a simple parameter, the TZ ratio, which predicts the efficacy of TUMT.