From the Guidelines
The normal prostate volume in adult men ranges from approximately 20 to 30 cubic centimeters (cc) or milliliters (mL). This volume typically increases with age due to benign prostatic hyperplasia (BPH), a common condition in older men. By age 60, many men have prostates measuring 30-40 cc, while volumes exceeding 40 cc are generally considered enlarged 1. Prostate volume can be accurately measured using transrectal ultrasound (TRUS), MRI, or CT imaging. These measurements are clinically important when evaluating symptoms of urinary obstruction, planning treatments for BPH, or monitoring prostate cancer. The increase in prostate size with age occurs primarily in the transition zone of the prostate due to hormonal changes, particularly the altered ratio of dihydrotestosterone (DHT) to testosterone. Some key points to consider when evaluating prostate volume include:
- A minimum prostate volume of >30cc or PSA >1.5ng/mL is necessary for a reliable 5-ARI response, but the larger the gland, the more pronounced the effects 1
- Treatment with 5-ARIs and combination therapy hinges on prostate volume and PSA threshold; therefore, obtaining imaging with TRUS (or reviewing existing cross-sectional imaging) to objectively assess prostate size is reasonable, with reservation of 5-ARIs for those with appropriately enlarged glands 1
- 5-ARI therapy can be utilized in appropriately enlarged prostates as prevention for BPH as it alters the natural history thereof 1 While prostate enlargement is common with aging, significant enlargement causing urinary symptoms may require medical intervention with alpha-blockers, 5-alpha-reductase inhibitors, or surgical procedures depending on symptom severity and impact on quality of life.
From the Research
Normal Prostate Volume
The normal volume of the prostate gland can vary depending on age and other factors.
- A study published in the International Journal of Urology 2 defined a normal prostate as less than 20 mL.
- Another study published in the Ethiopian Medical Journal 3 found that the mean and median prostate volume in Ethiopian males above 40 years was 42cc and 35cc, respectively.
- A study in the World Journal of Urology 4 found that the mean total prostate volume in community-dwelling men in Germany aged 50-80 years continuously increased from 24 to 38 cc.
Prostate Volume and Age
Prostate volume tends to increase with age.
- The study in the Ethiopian Medical Journal 3 found that peak prostate volume was seen in the seventh decade of life, and the volume of the prostate progressively increases with age.
- The study in the World Journal of Urology 4 also found that mean total prostate volume continuously increased with age.
Comparison of Prostate Volume Measurement Methods
Different methods can be used to measure prostate volume, including transabdominal ultrasound (TAUS) and digital rectal examination (DRE).
- The study in the International Journal of Urology 2 used TAUS to measure prostate volume.
- The study in the Canadian Journal of Urology 5 compared DRE and transrectal ultrasound (TRUS) measurements of prostate volume, and found that DRE had a positive predictive value of 94% in identifying prostates above 30 cc.