Prostate Specific Antigen (PSA)
Prostate-specific antigen (PSA) is a substance found in prostate cells that can be detected at a low level in the blood of all adult men. Checking PSA via regular blood tests is part of a man’s overall health monitoring, and it is one way to detect the development and progress of prostate cancer. The American Urologic Association, the American Cancer Society, and the National Comprehensive Cancer Network recommend that all men have annual PSA tests beginning at age 50, or as early as 40 – 45 if there is a family history of cancer, or if the man is African-American (rates of prostate cancer are historically higher among African-American men).
The PSA test goes along with a digital rectal exam (DRE) to help detect prostate cancer. During a DRE, a doctor inserts a gloved finger into the rectum and feels the prostate gland through the rectal wall to check for bumps or abnormal areas. By combining the results of the DRE and the PSA, doctors have a greater chance of detecting prostate cancer in men who have no symptoms of the disease.
There are known variations of PSA levels, with older men having slightly higher PSA measurements than younger men. Doctors watch for any significant increases in PSA levels – even if still in a normal range – as a sign of potential prostate cancer.
Greater-than-normal PSA levels also may indicate:
- Prostate enlargement (BPH or benign prostatic hypertrophy)
- Prostate infection (prostatitis)
- Urinary tract infection
- Recent urinary catheterization
- Recent urinary tract operation
This is why doctors will often opt to monitor PSA levels over time in order to determine what the associated condition might be rather than immediately assuming the worst. The doctor may look for a trend of rising PSAs over time rather than a single elevated PSA. The key is to remember that while a high PSA level has been linked to an increased chance of having prostate cancer it is not a definite sign of cancer. A high PSA level only identifies patients at higher risk of having prostate cancer. People at higher risk may need to have more tests in order to determine if, in fact, they have cancer.