Pretreatment prostate-specific antigen as an outcome predictor of targeted transurethral microwave thermotherapy

Abstract

Objectives. To evaluate pretreatment serum prostate-specific antigen (PSA) as an outcome predictor of targeted microwave thermotherapy. Methods. Seventy-one patients with lower urinary tract symptoms of benign prostatic hyperplasia underwent targeted transurethral microwave thermotherapy using the Targis system. Outcomes 12 months after treatment were evaluated by the International Prostate Symptom Score (IPSS), peak urinary flow rate (Qmax), and quality-of-life (QOL) score. The ability of PSA to predict outcomes was evaluated by linear and logistic regression and receiver operating characteristic curve analysis. Results. Higher pretreatment PSA levels were significantly predictive of an absolute IPSS change of −7.5 or less for patients with moderate baseline symptoms or −15 or less for those with severe baseline symptoms; an absolute Qmax change of 5 mL/s or greater; an absolute QOL score change of −3 or less; an IPSS at 12 months of 7 or less; a Qmax at 12 months of greater than 12 mL/s; and a QOL score at 12 months of 1 or less. Nevertheless, even without taking pretreatment PSA into account, most patients benefitted substantially from targeted microwave thermotherapy. Thus, 74%, 71%, and 79% of all eligible patients improved 50% or more in IPSS, Qmax, and QOL score, respectively, at 12 months compared with baseline. No significant association between PSA and either prostate or transition zone volume could be demonstrated. Conclusions. Most patients benefit substantially from targeted microwave thermotherapy. However, higher PSA levels are significantly predictive of more favorable outcomes. This association may reflect patient-to-patient differences in the relative abundance of PSA-producing epithelial cells in the transition zone of the prostate.