PSA (Prostate-specific antigen) is a protein made by both normal and cancerous prostate cells. It is found in the blood and can be measured with a blood test. The PSA test, which was first developed by the Roswell Park Cancer Institute, is often used to follow men after prostate cancer treatment. PSA testing is still being studied to see if finding cancer early lowers the risk of dying from prostate cancer.
PSA levels can rise if a man has prostate cancer but a high PSA is not proof of cancer. Other things can also make PSA levels go up, causing a false positive test result. These include having BPH or prostatitis, or disturbing the prostate gland in any way (including by riding a bicycle or motorcycle, having a DRE, orgasm in the past 24 hours, and prostate biopsy or surgery). Also, some prostate glands naturally produce more PSA than others. PSA levels go up with age. African-American men tend to have higher PSA levels in general than men of other races.
RPCI is known worldwide for its discoveries in prostate cancer, including serum PSA, which revolutionized prostate cancer detection and management. The diagnostic and screening programs are designed to detect prostate cancer early, when it is most treatable.
What do PSA results mean?
PSA levels are measured in terms of units per volume of fluid tested. Doctors often use a score of 4.0 nanograms (ng/ml) or higher as the trigger for further tests, such as a prostate biopsy.
Your doctor may monitor your PSA velocity, which means looking at the rate of change in your PSA levels over time. Rapid increases in PSA readings can suggest cancer. If you have a mildly elevated PSA, you and your doctor may choose to check PSA levels on a scheduled basis and watch for any change in the PSA velocity.
If your symptoms or test results suggest cancer, your doctor will refer you to a specialist (a urologist) for a prostate biopsy. A biopsy is usually done in the doctor's office, and involves the removal of small tissue samples from the prostate for examination under a microscope.
Digital Rectal Exam
During a digital rectal exam, or DRE, a doctor inserts a gloved, lubricated finger into the man's rectum to feel the prostate for any irregular or abnormally firm area that might be a cancer. The prostate gland is located directly in front of the rectum. Most prostate cancers begin in the part of the gland that is nearest the rectum and can be reached by a rectal exam.
This exam is also used once a man is known to have prostate cancer in order to help predict whether the cancer has spread beyond his prostate gland.
