New Study! Worse Prostate Cancer Outcomes With 5-Alpha-Reductase Inhibitors

June 17, 2019 10:16 am Published by

What Does It Mean For Prostate Cancer Patients?

A recent study, “5-alpha-reductase inhibitors delay prostate cancer diagnosis, worsen outcomes,” by Sarkar, RR, et al, published in JAMA Internal Medicine, May 2019, found that “prior use of 5-alpha-reductase inhibitors for benign prostatic hyperplasia (BPH) was associated with delayed prostate cancer diagnosis and worse prostate cancer outcomes.”  One reason for this is misinterpretation of screening test values when men are taking certain medications.

Prostate cancer screenings involve taking a prostate specific antigen (PSA) blood test. This simple blood test measures the level of PSA to help diagnose cancer.  If you are having your prostate cancer screening done by your primary care physician (PCP), it is important that you advise your doctor if you are using one of commonly prescribed 5-alpha-reductase medicines so that he or she can interpret the test result correctly.

Taking finasteride (Proscar®)” or dutasteride (Avodart®) for your urinary problems due to BPH results in inaccurate test results.  These medications artificially lower the true PSA by 47%.  While some think this is a good thing because an abnormal PSA may be brought into a normal range, the opposite is true.  For patients on these medications, the PSA value MUST be doubled for an accurate result.  For example, if your PSA is 2.4 that’s not correct – the true value is 4.8 which is abnormal. So, if you are taking any of these medications you MUST ask your PCP if they have calculated the true PSA.

Additionally, men taking Propecia® for hair loss may not be aware that it is a 5a-reductase inhibitor (finasteride). Since this medication is available over-the-counter, at a pharmacy or drug store, you MUST tell your doctor if you are taking Propecia.  Once again, the PSA value needs to be doubled for a true and accurate result.


There is conflicting information available on what PSA results mean. It is important to educate yourself on the various types of PSA tests and what the results mean.

PSA blood sample

A standard PSA test measures the total PSA in your blood. But PSA has many different forms and subtypes.  The two most common and practically available forms that should be measured annually are:

  • Bound – attached to a protein in the blood.  This is the TOTAL PSA.  It should not exceed 2.5 in men up to age 65 and should not be more than 4.0 in men over the age of 65.
  • Unbound – this means PSA is not attached to blood proteins. This is the FREE PSA.

The proportions of free and bound PSA are different in men with prostate cancer, compared to men who have benign prostate disease. It is a general opinion that a higher amount of free PSA in a test means a lower chance of cancer. Levels above 25% are typically thought to be normal.  Levels below this may be an early sign of prostate cancer even when the total (bound) PSA is normal.


The best advice I can give is that all men over 50 should have an annual prostate cancer screening.  Start 10 years earlier if there’s a family history of prostate cancer. In general, it’s best to have it done by a urologist because we are skilled in doing thorough prostate exams and in interpreting PSA results.  Read more about understanding prostate cancer diagnosis.


As always if you have any further questions, please contact us today!

This post was written by Western States HIFU