2 Minute ReadWhat is PSA?
PSA, or Prostate-Specific Antigen, is a protein produced by both normal and cancerous cells in the prostate — a small gland located just below your bladder. While PSA is primarily found in semen, a small amount also circulates in your blood. A PSA test measures that level in your bloodstream and is one of the key tools used to screen for prostate cancer.
How is PSA Used in Prostate Cancer Diagnosis?
A PSA level that is higher than normal can be a sign of prostate cancer. Your doctor may use the PSA test alongside a digital rectal exam (DRE) to help detect cancer in its early stages. Your doctor will also look at how your PSA levels change over time — a rising trend can be just as informative as a single result. Generally, a level above 4 ng/mL may be considered abnormal and worth investigating further.
That said, the PSA test isn’t perfect. It can sometimes suggest cancer when none is present (a false positive), or miss cancer when it is there (a false negative). Elevated PSA levels can also be caused by other conditions, such as an enlarged prostate (benign prostatic hyperplasia) or a prostate infection (prostatitis). Your doctor will take all of this into account when interpreting your results.
How is PSA Used in Active Surveillance?
If your prostate cancer is considered low risk, your doctor may recommend active surveillance — meaning you’ll be closely monitored rather than treated right away. As part of this approach, you’ll typically have a PSA test every six months. Steady or only slightly rising PSA levels can be a reassuring sign that the cancer is stable and not becoming more aggressive. Periodic MRI scans and repeat biopsies are also important parts of staying on top of things during active surveillance.
How is PSA Used to Monitor treatment?
After surgery or radiation for prostate cancer, your PSA levels will be tested regularly — typically every three to six months for the first five years. A decrease in your PSA levels is often a positive sign that your treatment is working. These check-ins are an important part of making sure you stay on the right track.
