What are normal prostate size measurements?

From the Guidelines

The normal adult prostate gland typically measures 3-4 cm in width, 2-3 cm in height, and 4-5 cm in length, with a total volume ranging from 20 to 30 cubic centimeters (cc) or milliliters (mL). This is based on the most recent evidence from urology guidelines, including the 2021 AUA guideline on the management of lower urinary tract symptoms attributed to benign prostatic hyperplasia 1.

Key Points to Consider

• Prostate volume is commonly calculated using the ellipsoid formula (width × height × length × 0.52), with volumes under 30 cc considered normal in adult men.
• During digital rectal examination, a normal prostate should feel smooth, rubbery, and symmetrical with a palpable median sulcus.
• The prostate's size is clinically significant as enlargement can cause urinary symptoms, while abnormal nodules or asymmetry may indicate potential malignancy.
• Prostate-specific antigen (PSA) levels typically correlate with prostate size, with normal levels generally below 4 ng/mL, though this varies by age, as noted in the context of managing LUTS/BPH 1.

Clinical Significance

Regular prostate examinations are recommended for men over 50, or earlier for those with risk factors, to monitor for changes in size or texture. The size of the prostate is a critical factor in determining the appropriate treatment for benign prostatic hyperplasia (BPH), with combination therapy, including 5-ARI and alpha blockers, recommended for patients with prostates larger than 30 cc 1. In contrast, for smaller prostates (≤30g), transurethral incision of the prostate (TUIP) may be offered as an option for the treatment of LUTS/BPH, as indicated by the 2018 AUA guideline 1. However, the most recent and highest quality evidence should always guide clinical decisions, prioritizing patient outcomes in terms of morbidity, mortality, and quality of life.

From the FDA Drug Label

In A Long-Term Efficacy and Safety Study, prostate volume was assessed yearly by magnetic resonance imaging (MRI) in a subset of patients. In patients treated with finasteride tablets who remained on therapy, prostate volume was reduced compared with both baseline and placebo throughout the 4-year study. Finasteride tablets decreased prostate volume by 17.9% (from 55.9 cc at baseline to 45.8 cc at 4 years) compared with an increase of 14.1% (from 51.3 cc to 58.5 cc) in the placebo group (p<0.001). The mean prostate volume at baseline ranged between 40 to 50 cc. The mean prostate volume at trial entry was approximately 54 cc

The normal prostate measurements are not explicitly stated in the provided text, but the mean prostate volume at baseline in the studies ranged from 40 to 50 cc and was approximately 54 cc at trial entry. 2 3

From the Research

Normal Prostate Measurements

• The normal prostate size can vary, but it is generally considered to be around 20-30 mL in volume 4.
• Prostate size can be an important factor in the treatment of benign prostatic hyperplasia (BPH), with larger prostates potentially requiring more aggressive treatment 5.
• Studies have shown that 5-alpha reductase inhibitors, such as finasteride and dutasteride, can reduce prostate size and improve symptoms in men with BPH 6, 7.
• However, the effectiveness of these treatments can depend on the size of the prostate, with some studies suggesting that they are more effective in men with larger prostates 4, 5.

Prostate Size and Treatment Outcomes

• A study published in 2010 found that finasteride was more effective in improving urinary symptoms in men with larger prostates (≥ 40 mL) compared to those with smaller prostates (< 25 mL) 4.
• Another study published in 2022 found that dutasteride was more effective than finasteride in improving maximum urinary flow rate (Qmax) in men with BPH, but there was no significant difference in terms of reducing International Prostate Symptom Score (IPSS) or improving quality of life (QOL) 5.
• A systematic review and meta-analysis published in 2017 found that there was no significant difference in the efficacy and safety of finasteride and dutasteride in terms of clinically important outcomes, including need for prostate-related surgery, episodes of acute urinary retention, and sexual dysfunction 7.

Alpha-Blockers and Prostate Size

• Alpha-blockers, such as alfuzosin, doxazosin, tamsulosin, and terazosin, can reduce bladder outflow resistance and improve urinary flow in men with BPH, regardless of prostate size 8.
• However, the effectiveness of alpha-blockers can depend on the severity of symptoms and the degree of subvesical obstruction, with some studies suggesting that they are more effective in men with mild to moderate symptoms 8.