From the Research
The normal prostate size on ultrasound is generally considered to be less than 20 mL in volume, as defined in a study published in 2010 1. This definition is based on the use of transabdominal ultrasound (TAUS) to measure prostate volume and assess the degree of intravesical prostatic protrusion (IPP). The study found that a normal prostate shows no IPP and has a maximum flow rate of more than 15 mL/s. Other studies have also investigated the correlation between prostate volume and symptoms severity score in patients with benign prostatic hypertrophy (BPH) 2, and the accuracy of digital rectal examination in estimating prostate volume 3. However, the most recent and highest quality study on the topic of prostate size measurement is a 2020 study that compared the accuracy of transabdominal and transrectal ultrasound for sizing of the prostate 4. This study found that transabdominal ultrasound is interchangeable with transrectal ultrasound in estimating prostate volume for prostates less than 30 cm3, but recommended transrectal ultrasound or cross-sectional imaging for larger prostates. Key points to consider when assessing prostate size on ultrasound include:
- The use of transabdominal or transrectal ultrasound to measure prostate volume
- The calculation of prostate volume using the ellipsoid formula: width × height × length × 0.52
- The correlation between prostate volume and symptoms severity score in patients with BPH
- The accuracy of digital rectal examination in estimating prostate volume
- The importance of considering prostate size in the diagnosis and treatment of BPH and other prostate conditions. In clinical practice, a prostate size of less than 20 mL is generally considered normal, and larger prostates may indicate BPH or other conditions requiring further evaluation and treatment 1.