5α-Reductase inhibitor is less effective in men with small prostate volume and low serum prostatic specific antigen level.
OBJECTIVE
Large total prostate volumes (TPVs) or high serum prostate-specific antigen (PSA) levels indicate high-risk clinical progression of benign prostatic hyperplasia. This prospective study investigated the treatment outcome of combined 5α-reductase inhibitor and α-blocker in patients with and without large TPVs or high PSA levels.


METHODS
Men aged ≥ 45 years with International Prostate Symptom scores (IPSS) ≥ 8, TPV ≥ 20 mL, and maximum flow rate ≤ 15 mL/s received a combination therapy (dutasteride plus doxaben) for 2 years. Patients with baseline PSA ≥ 4 ng/mL underwent prostatic biopsy for excluding malignancy. The changes in the parameters from baseline to 24 months after combination therapy were compared in those with and without TPV ≥ 40 mL or PSA levels ≥ 1.5 ng/mL.


RESULTS
A total of 285 patients (mean age 72 ± 9 years) completed the study. Combination therapy resulted in significant continuous improvement in IPSS, quality of life index, maximum flow rate, and postvoid residual (all p < 0.0001) regardless of baseline TPV or PSA levels. However, only patients with baseline TPV ≥ 40 mL had significant improvements in IPSS-storage subscore, voided volume, reduction in TPV, transitional zone index, and PSA levels. In addition, patients with baseline TPV < 40 mL and PSA < 1.5 ng/mL had neither a reduction in TPV nor a decrease in serum PSA level.


CONCLUSIONS
A high TPV indicates more outlet resistance, whereas elevated serum PSA level reflects glandular proliferation. Thus, patients with TPV<40 mL and low PSA levels has less benefit from 5α-reductase inhibitor therapy. The therapeutic effect of combined treatment may arise mainly from the α-blocker in these patients.
Department of Urology, E-Da Hospital, Kaohsiung, Taiwan; Department of Healthcare Administration, I-Shou University, Kaohsiung, Taiwan.
Victor C
VC
Lin
Department of Urology, Cardinal Tien Hospital, and School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan.
Chun-Hou
CH
Liao
Department of Urology, En Chu Kong Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.
Chung-Cheng
CC
Wang
Department of Urology, Buddhist Tzu Chi General Hospital, and Tzu Chi University, Hualien, Taiwan. Electronic address: hck@tzuchi.com.tw.
Hann-Chorng
HC
Kuo
D058891:5-alpha Reductase Inhibitors / Q000008:administration & dosage*; D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage*; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D016009:Chi-Square Distribution; D018450:Disease Progression; D017292:Doxazosin / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D000068538:Dutasteride / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000188:drug therapy* / Q000473:pathology; D011788:Quality of Life; D013624:Taiwan; D016896:Treatment Outcome
D058891:5-alpha Reductase Inhibitors; D000317:Adrenergic alpha-Antagonists; D017430:Prostate-Specific Antigen; D017292:Doxazosin; D000068538:Dutasteride
5α-reductase inhibitor; benign prostatic hyperplasia; prostatic specific antigen; total prostatic volume