The response to alpha blockade in benign prostatic hyperplasia is related to the percent area density of prostate smooth muscle.

The objective of the present study was to determine whether the smooth muscle content of the prostate adenoma is related to the clinical response to terazosin, a long-acting selective alpha 1 blocker. Multiple random biopsies of the prostate were obtained from 26 male subjects with symptomatic benign prostatic hyperplasia (BPH) prior to initiating therapy with terazosin. Double immunoenzymatic staining and computer-assisted quantitative color image analysis were utilized to quantify the area density of smooth muscle, connective tissue, glandular epithelium, and glandular lumen. The clinical response to alpha blockade was based upon changes in peak urinary flow rate and the Boyarsky symptom score. A significant direct relationship was observed between the percent area density of smooth muscle and the percent change in peak urinary flow rate. A statistically significant correlation between the percent area density of smooth muscle and the percent change in Boyarsky symptom score was not observed. The percent area density of prostate smooth muscle in the subjects exhibiting a favorable clinical response was 38% greater than the nonresponders (P = 0.068). The clinical response to alpha blockade in BPH is related to the area density of prostate smooth muscle.