PSA/ Prostate Specific Antigen

Cystoscopy :: Digital Rectal Examination ::  Pathology
PSA :: Radiology :: Urodynamics :: TRUS

Normal Ranges for PSA

• Abnormal PSA - Men with a PSA above the 95th percentile for age may have prostate cancer and should be referred to a Urologist for assessment
  
  
• Men with a PSA above the median (50th percentile) but below the 95th percentile are at a higher long term risk for cancer and require close follow up
  
  
• PSA Velocity - A normal rate of change for PSA is 0.04ng/ml/yr, or 3.3%
• A PSA rising at greater than 0.5 ng/ml/yr. is suspicious for cancer and should trigger referral
  
  
• Percentage free PSA (FTR) can help distinguish non cancer from cancer causes for PSA elevation in the range 2-10. A FTR less than 10% is suspicious for cancer. A higher level does not exclude cancer
  
  
• False negatives - Between 10%-30% of men with prostate cancer have a normal PSA for age with the rectal examination or PSA velocity the only abnormalities

What can affect PSA levels apart from cancer?

• PSA velocity is unaffected by the listed agents that lower PSA and should be used as an important guide for these patients
• Bike riding has been shown not to affect PSA levels

When to refer?

• When the PSA exceeds the upper limit of normal for age (95th percentile)
• PSA rate of change exceeds 0.5ng/ml/yr
• Digital Rectal Examination is suspicious

When to follow up?

• PSA in the upper ranges of normal (exceeds median)
• Patient has a family history of prostate cancer (each relative increases the risk by 2.5 times)
• Patient requests testing for early detection and should be checked annually

When to commence testing?

The Urological Society of Australia and New Zealand recommends a first PSA test at the age of 40. Patients with a PSA above the median can then be closely watched to allow the early detection of their disease.

Conclusion

For those patients interested in the early detection of prostate cancer, their GP plays a pivotal role. All major prostate cancer bodies advocate the use of the PSA decision card in helping GPʼs understand how to use the test to the greatest benefit of patients. As men are living longer and other pathologies are less likely to kill, prostate cancer has become a more serious issue in this country. Prostate cancer is unlike other cancers due to its proximity to critical continence and erectile structures that are difficult to preserve without early detection.