Clinical characteristics of alpha-blocker responders in men with benign prostatic hyperplasia

Currently, alpha-blocker is becoming first-line drug therapy for benign prostatic hyperplasia (BPH). Although highly effective results are obtained with this therapy, a difference between the objective and subjective response rates is reported. To prevent unnecessary medical treatment and to predict the alpha-blocker response, we characterized the clinical features of alpha-blocker responders in men with BPH.

Twenty-two men were consecutively enrolled in this study and received tamsulosin 0.2 mg once daily for 4-6 weeks. The primary measures of efficacy were maximum urinary flow rate (Q(max)) determined from the flow measurements and international prostate symptom score (IPSS). Those with an increase in Q(max) of > or = 30% from baseline and a decrease in IPSS of > or = 25% from baseline were defined as Q(max) responders and IPSS responders, respectively. Clinical findings such as age, pretreatment IPSS and Q(max), serum prostate-specific antigen (PSA), total prostate volume, transition zone (TZ) volume, TZ index and T(2)-weighted magnetic resonance image (MRI) of the prostate TZ were compared between responders and non-responders for both criteria.

In 17 of 22 (77.2%) patients IPSS improved by > or = 25%. In 9 of 22 (40.9%) patients Q(max) improved by > or = 30%. There were no differences in clinical findings between IPSS responders and non-responders. On the contrary, Q(max) responders showed smaller total prostate and TZ volumes, a smaller TZ index and a lower intensity of the TZ in MRI than Q(max) non-responders.

Determination of the prostate volume and MRI findings of the inner prostate gland were useful in predicting Q(max) responders to the alpha-blocker in men with BPH. In contrast, there were no clinical characteristics of the IPSS responders. IPSS responders without a Q(max) response should be closely followed while continuing the alpha-blocker therapy for a long duration.