From the Guidelines
The size of a prostate can be most accurately measured through transrectal ultrasound (TRUS), as it allows for the calculation of prostate volume using the ellipsoid formula (length × width × height × 0.52) 1.
Methods of Measurement
- Digital rectal examination (DRE) is the most common initial assessment, where a healthcare provider inserts a gloved, lubricated finger into the rectum to feel the prostate gland, estimating its size and detecting any abnormalities.
- Transrectal ultrasound (TRUS) is typically used for more precise measurements, where an ultrasound probe is inserted into the rectum to create images of the prostate.
- MRI provides the most accurate measurements and can detect subtle abnormalities, though it's more expensive and not routinely used for size assessment alone.
- CT scans can also visualize the prostate but offer less detail than MRI.
- Blood tests for prostate-specific antigen (PSA) levels can indirectly indicate prostate enlargement but don't directly measure size.
Importance of Measurement
Regular prostate size assessment is important for monitoring conditions like benign prostatic hyperplasia (BPH) and prostate cancer, with significant changes potentially indicating disease progression requiring medical intervention 1.
Calculation of Prostate Volume
The prostate volume is an important criterion for interventional treatment selection and can predict the risk of symptom progression and BPO-related complications 1.
Normal Prostate Volume
Normal prostate volume varies by age, typically ranging from 20-30 cubic centimeters in younger men and potentially larger in older men.
Recent Guidelines
According to the 2023 European Association of Urology guidelines, physical examination and digital rectal examination can estimate prostate volume, but ultrasonography (US) is more accurate 1.
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. The mean prostate volume as measured by transrectal ultrasound was 36.3 mL (±20. 1 mL). The size of a prostate can be measured by magnetic resonance imaging (MRI) or transrectal ultrasound.
From the Research
Methods for Measuring Prostate Size
- Digital Rectal Examination (DRE): This method involves a physician inserting a gloved finger into the rectum to estimate the size of the prostate 2, 3, 4, 5.
- Transrectal Ultrasound (TRUS): This method uses high-frequency sound waves to create images of the prostate, allowing for accurate measurement of its size 2, 6, 3, 4.
- Magnetic Resonance Imaging (MRI): This method uses a strong magnetic field and radio waves to create detailed images of the prostate, allowing for accurate measurement of its size 6.
Accuracy of Measurement Methods
- DRE tends to underestimate prostate size, particularly for larger prostates 2, 3, 4.
- TRUS is generally considered to be more accurate than DRE for measuring prostate size 2, 6, 3, 4.
- MRI has been shown to be an accurate and reliable method for measuring prostate size, and may be more cost-effective and time-efficient than TRUS 6.