DESCRIPTION
Prostate specific antigen (PSA) is a protein produced only by the prostate
gland. The prostate gland is a doughnut-shaped gland that sits in a man's pelvis
in the small space between the base of the penis and the bladder. It makes
nutrients for sperm. The amount of PSA produced by a man's prostate gland can be
helpful in detecting and monitoring prostate cancer. The amount of PSA produced
by the prostate has been shown to increase when a man has prostate cancer. PSA
is one of the latest markers to help in both early diagnosis and treatment of
prostate cancer.
Prostate cancer has become the most commonly diagnosed cancer among men in the
United States. It is now the second leading cause of cancer deaths among males.
The prostate cancer death rate is especially high among African-American males.
African-American men have the highest rate of death from prostate cancer in the
world.
PSA can be measured with a simple blood test. It is an important breakthrough
because prostate cancer is usually silent in early stages. Normal levels, which
increase slightly with age, have been determined. The PSA blood test indicates
whether the amount of PSA is within the normal range.
There is some controversy about the value of the PSA blood test and whether it
should be done routinely for men over a certain age. However, the American
Cancer Society recommends that all men begin having annual prostate cancer
screenings at age 50, a rectal exam and a serum PSA level. If you are at
increased risk for prostate cancer, discuss when to begin screening with your
health care professional.
BENEFITS OF PSA SCREENING
- Simple blood test
- Less expensive than other tests, such as ultrasound scans
- Better at detecting small cancers that cannot be found with a physical
exam
- Can evaluate the effectiveness of treatment of men who have prostate
cancer
- Will help detect recurrence of cancer
LIMITATIONS OF PSA SCREENING
- The test is normal in 25 percent to 45 percent of men with prostate cancer
- Prostate infection and prostate enlargement (benign prostatic hypertrophy)
can increase the PSA level also
Because of limitations to PSA screening, the test is most
helpful when evaluated by your health care provider in the context of your
history, physical exam and other testing that is necessary.
