PSA (prostate specific antigen) is also used to monitor men who have been treated for prostate cancer to see if they remain cancer-free.
Elevated PSA levels in a man who has never been treated for prostate cancer may be a sign of any prostate problem. PSA rise may indicate prostatitis (infection). It may indicate benign growth or swelling of the prostate (BPH). Or it may indicate prostate cancer.
PSA is made in the prostate. It is measured in nanograms per milliliter of blood. Normally, PSA levels in the blood remain very low. Any hurt to or injury of the normal prostate, such as from inflammation caused by infection, may cause more PSA to leak into the bloodstream.
In the past, most doctors considered PSA values below 4.0 ng/ml as normal. However, recent research found prostate cancer in men with PSA levels below 4.0 ng/ml. Many doctors are now using the following ranges, with some variation:
- 0 to 2.5 ng/ml is low
- 2.6 to 10 ng/ml is slightly to moderately elevated
- 10 to 19.9 ng/ml is moderately elevated
- 20 ng/ml or more is significantly elevated
This new approach reflects the fact that relatively low PSA levels in the blood may mask some aggressive prostate cancers.
Rate of PSA over time is a key factor in diagnosing prostate cancer. This is sometimes called PSA velocity and sometimes calculated as "PSA doubling time." In men with prostate cancer, tumor doubling time ranges from a month or two to over 12 or 15 years. PSA doubling time is a pretty reliable indicator of cancer cell doubling although not a sufficient indicator without biopsy and imaging scans.
Do I need a PSA test to screen for prostate cancer?
Regular PSA test followed by rectal exam is the most effective method available for the early detection of prostate cancer.
Since the PSA test came into use in the United States, the death rate for prostate cancer has fallen from some 40,000 deaths per year to 27,000 deaths per year predicted for 2007.
PSA testing and the digital rectal examination (DRE) "are crucial in detecting prostate cancer in its early stages, when it usually produces no physical symptoms," researchers at University of Pittsburgh Cancer Institute say.
A study from Dana-Farber and Brigham and Women's Hospital indicates that the rate at which PSA levels rise (called PSA velocity) may be more important for predicting the danger of prostate cancer than PSA levels as such.
Most US guidelines for prostate cancer screening recommend annual PSA and digital rectal exam (DRE) in these circumstances:
- By age 40 for African American men and men with family history of prostate cancer or mother with breast cancer.
- PSA by age 40 for is advised for all men as a baseline measure for tracking PSA velocity (rate of rise) over the next ten years.
- A recommended approach is to take a PSA test by age 40, with biopsy if PSA is 2.5 ng/mL or higher. If you have no special risk, retest every two years.
- After age 50 men are advised to take a PSA and rectal exam every year until age 70.
Is there an age for stopping PSA tests?
Men in their seventies and beyond may or may not wish to continue PSA and rectal exam testing.
The choice of what to do about prostate cancer is separate from finding out whether you have it. But these choices narrow if prostate cancer goes undiscovered until a later stage.
Treating prostate cancer in elderly men extends lives compared to Watchful Waiting, according to a 2006 study by Fox-Chase cancer center.
But Johns Hopkins' specialist Dr. H. Ballentine Carter noted in 2005 that benefits of prostate cancer screening decline with age.
This clash of opinions probably involves comparing apples and oranges -- with a little bit of "cherry-picking" thrown in.
If you are a man in your seventies or above, talk to your family doctor or internist about your overall health picture. And talk to your urologist about how prostate cancer fits into this picture as you age.
If you have any chronic conditions like heart disease or diabetes, discuss how these affect your longevity. Look for ways to protect yourself against late-age prostate cancer in case you outlive your other ailments.
Regular exercise and some simple, pleasant improvements in your diet that will fit in with your overall health needs might protect you against aggressive prostate cancer in your final years.
If you are diagnosed with an early stage, slow-growing prostate cancer in your seventies, say, would you prefer to meet it head on and deal with side effects of treating it? Or would you prefer a wait and watch approach?
How might you feel if ceasing PSA tests and rectal exams at age 70 led to late-detection of a prostate cancer at age 75? Hindsight is 20-20 but might you feel relieved that at least you had enjoyed a few extra years free of worry and possible treatment side effects? Or might you feel that you had passed up opportunities to cure the cancer at an early stage?
Questions to keep in mind at any age include:
Is this a threat to my life or health and well-being soon or in the mid to distant future? Which treatments, if any, offer a good chance of cure? or failing cure, which treatments are most likely to minimize any threat prostate cancer poses to my health? Which options have least least harmful impact on my erectile function, libido, urinary continence, bowel function and overall quality of life?
PSA tests for men who have been treated for prostate cancer
In men already treated for prostate cancer, the PSA test helps to monitor whether the treatment has worked and to watch for possible recurrence.
About one third of men who are treated for prostate cancer at any age experience recurrence. The first indication of recurrence is a rising PSA. This may be the only sign of recurrence for months or for many years. If so the man has what is called "biochemical recurrence."
PSA tests for monitoring purposes after primary treatment should be extra "sensitive." Measurements to several decimal points make a difference when deciding whether PSA is rising after surgery
After treatments radiation, whether external beam or seeding implants, some men experience a PSA "bounce," which is not a sign of recurrence.
Some treatments for advanced prostate cancer can halt or slow tumor doubling time as measured by PSA. But PSA alone is not a reliable measure of progression or control in advanced prostate cancer. Regular scans by MRI, CT, and nuclear bone scan are essential.
Thompson IM, Pauler DK, Goodman PJ, et al. Prevalence of prostate cancer among men with a prostate-specific antigen level [less than or equal to] 4.0 ng per milliliter. The New England Journal of Medicine 2004; 350(22):2239–2246.
Two ways of using the PSA test for diagnostic purposes are laid out in our CHECK UP FLOWCHART 1 and CHART #2 USING "free" PSA. Also see:
Find Life-Threatening Prostate Cancer by Measuring PSA Velocity During "Window of Curability" Nov 1, 2006.
PSA Bounce not a sign of recurrence 2004
This page made by J. Strax, last updated December 26, 2008.