INTRODUCTION - We investigated the value of the transitional zone index (TZI) for predicting treatment response to combination therapy involving α-blockers and 5α-reductase inhibitors for benign prostatic hyperplasia (BPH).
MATERIALS AND METHODS - Symptomatic BPH patients (n = 118) were randomized to receive 0. 2 mg tamsulosin alone or with 0. 5 mg dutasteride daily for 12 months. The TZI, International Prostate Symptom Scores, maximum urinary flow rates (Qmax), postvoid residual urine volumes, and prostate-specific antigen (PSA) were evaluated at baseline and after 12 months. The groups were subdivided according to a cut-off TZI value of 0. 5 to compare treatment-related changes.
RESULTS - After 12 months, the combination therapy group had significantly greater decreases in prostate volume (p < 0. 001), TZ volume (p < 0. 001) and PSA (p < 0. 001) than the monotherapy group, regardless of TZI. However, combination therapy resulted in significantly greater Qmax increases (p < 0. 001) only in patients with a TZI ≥0. 5. Multivariate analysis determined that TZI was the strongest independent predictor of the Qmax increase at 12 months in the combination therapy group (β = 13. 7, p < 0. 001).
CONCLUSIONS - Greater Qmax improvement is expected with combination therapy comprising α-blockers and 5α-reductase inhibitors for patients with a TZI ≥0. 5. The TZI may be useful for predicting the Qmax response to combination treatment for BPH.
Urologia internationalis. 2016 Jan 30 [Epub ahead of print]
Jae Duck Choi, Jung Hoon Kim, Seung Hyun Ahn
Department of Urology, KEPCO Medical Center, Seoul, Republic of Korea.