Webster's New World Medical Dictionary

prospective study
A study in which the subjects
are first identified and then followed forward as
time passes.
prostaglandin
A hormone-like substance that
participates in a wide range of body functions such
as the contraction and relaxation of smooth muscle,
the dilation and constriction of blood vessels, con-
trol of blood pressure, modulation of inflammation,
and production of the normal protective mucus lin-
ing of the stomach. Prostaglandins are derived from
a chemical called arachidonic acid.
prostate
See 
prostate gland.
prostate, nodular hyperplasia of the
See
benign prostatic hyperplasia.
prostate acid phosphatase
An enzyme that is
produced by the prostate gland that is elevated in
some patients with prostate cancer.
prostate cancer
See 
cancer, prostate.
prostate enlargement
Overgrowth of the
prostate gland, usually due to a common, benign,
and very treatable condition known as benign pro-
static hyperplasia (BPH). Far fewer cases of
prostate enlargement are due to prostate cancer.
See also 
digital rectal exam; prostate cancer;
prostate gland; prostate specific antigen test;
prostatic hyperplasia, benign.
prostate gland
A gland in the male reproductive
system that is located just below the bladder. It sur-
rounds part of the urethra, the canal that empties
the bladder. The prostate gland helps to control uri-
nation, and it forms part of the content of semen.
Also known as simply the prostate.
prostate specific antigen test
A blood test that
is used to screen for cancer of the prostate and to
monitor treatment. Prostate specific antigen (PSA)
is a protein that is produced by the prostate gland.
If elevated levels of PSA are detected in the blood,
additional testing is needed if it is being used as a
screening measure. An elevated level of PSA is not
specific to prostate cancer. Other diseases can
cause elevated PSA, including benign prostatic
hypertrophy (BPH), an increase in the size of the
prostate that typically occurs with aging. Infection of
the prostate gland (prostatitis) is another relatively
common cause of elevated PSA. Many early cancers
do not produce enough PSA to cause a significantly
abnormal blood level. It is therefore important not
to rely only on blood PSA testing. The most useful
additional test is a physical prostate exam known as
the digital rectal exam. See also 
digital rectal
exam; prostate cancer; prostate gland; prostatic
hyperplasia, benign.
prostatectomy
Surgical removal of the prostate
gland. Prostatectomy can be done through an inci-
sion in the abdomen or through the urethra
(transurethral resection).