No relationship between prostate volume at the start of treatment and short-term treatment efficacy of tamsulosin was found in a study entitled “Does Baseline Prostate Volume Affect the Short-Term Outcome of Tamsulosin?“ published in the journal LUTS: Lower Urinary Tract Symptoms.

Adrenergic alpha-1 blocking drugs such as tamsulosin (Flomax) are the standard treatment for symptoms of benign prostatic hyperplasia (BPH). They work by relaxing the muscles of the prostate and bladder neck, allowing urine to flow more easily. Other drugs in this category include terazosin (Hytrin), doxazosin (Cardura), alfuzosin (Uroxatral), and silodosin (Rapaflo).

Previous studies, including a study by the same group, have shown that treatment with alpha-blockers is not effective in the long-term for a subset of patients with large prostate volume. However, in spite of treatment recommendations, few studies to date have examined the short-term efficacy of alpha-blockers for BPH in relation to prostate volume.

This study enrolled 112 patients with lower urinary tract symptoms indicating BPH and measured prostate volume using ultrasound. Patients were divided into a high prostate volume and a low prostate volume group. The team analyzed the efficacy of tamsulosin not only by measuring International Prostate Symptom Scores but also by analyzing the BPH problem index and measuring quality of life factors.

Measuring symptoms after four weeks and again after three months, researchers found that tamsulosin effectively reduced BPH symptoms in both the high volume and the low volume group. The results confirm findings from three previous studies, showing no effect of prostate volume on treatment efficacy of tamsulosin. Other alpha-1 blockers have also been investigated in similar ways, finding no relationship between prostate volume at treatment onset and efficacy of the drug.

While the authors note the limitations of the study — a relatively small number of participants and no control group receiving placebo —  they argue that the analysis they used is robust enough to contribute with solid data to the already large body of evidence to support the recommendation of tamsulosin and other alpha-blockers for the initial treatment of BPH symptoms.