From the FDA Drug Label
The mean prostate volume at baseline ranged between 40 to 50 cc. The mean prostate volume as measured by transrectal ultrasound was 36.3 mL (±20.1 mL). Prostate volume was ≤20 mL in 16% of patients, ≥50 mL in 18% of patients and between 21 and 49 mL in 66% of patients A prostate volume of at least 30 cc measured by transrectal ultrasound was required for trial entry. The mean prostate volume at trial entry was approximately 54 cc
The normal size for a prostate is not explicitly stated in the drug labels, but the mean prostate volume at baseline in the studies ranged from approximately 36.3 mL to 54 cc, with most patients having a prostate volume between 21 and 49 mL 1 2.
- Mean prostate volume: 36.3 mL to 54 cc
- Prostate volume range: ≤20 mL to ≥50 mL
- Most common range: 21-49 mL
From the Research
The normal size of a prostate gland in an adult male is approximately 20-30 grams or about the size of a walnut (roughly 3 cm x 4 cm x 2 cm in dimensions). The prostate naturally grows throughout a man's life, with this growth accelerating after age 40 due to hormonal changes. This enlargement, known as benign prostatic hyperplasia (BPH), is common as men age and isn't necessarily concerning unless it causes symptoms. By age 60, about half of men have some prostate enlargement, and by age 85, this increases to about 90%. The prostate's size is typically measured during a digital rectal exam or more precisely through ultrasound or MRI imaging. A prostate weighing more than 30-40 grams is generally considered enlarged. The size matters clinically because an enlarged prostate can compress the urethra and cause urinary symptoms such as weak stream, frequency, urgency, and incomplete emptying. However, the severity of symptoms doesn't always correlate directly with prostate size - some men with significantly enlarged prostates have minimal symptoms, while others with modest enlargement may experience significant discomfort.
Key Points to Consider
- The size of the prostate can be measured through digital rectal examination or imaging techniques like ultrasound or MRI 3, 4, 5, 6, 7.
- Prostate size is an important factor in determining the risk of urinary symptoms and other complications 3, 4, 5, 6, 7.
- The most recent and highest quality study, published in 2024, suggests that digital rectal examination may not be necessary for routine prostate cancer screening 7.
- The normal size range for a prostate gland is a critical factor in assessing prostate health and guiding clinical decision-making.
Clinical Implications
- Clinicians should be aware of the normal size range for the prostate gland and consider this when evaluating patients for prostate-related symptoms or conditions.
- The use of digital rectal examination and prostate-specific antigen (PSA) testing should be guided by current evidence and clinical guidelines 3, 4, 5, 6, 7.
- A prostate size of 20-30 grams is generally considered normal, but individual variations and clinical context should be taken into account.
Evidence-Based Recommendations
- Clinicians should prioritize the use of evidence-based guidelines and current research when evaluating and managing prostate health 3, 4, 5, 6, 7.
- The most recent and highest quality study should be used to inform clinical decision-making, in this case, the 2024 study published in European urology oncology 7.