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The male sex hormone testosterone
feeds the growth of prostate cells and prostate cancer.
Male hormones are called androgens. Prostate cancer
hormone therapy works by ablating or depriving testosterone
in the body. With no hormone to fuel their growth, the
cells stop growing. Hormone therapy does not provide
a cure; the prostate cancer does not “starve”
to death, but for a time the spread of the disease can
be slowed or even halted.
Hormone
therapy is most versatile of the postate cancer treatments.
the ablation and deprivation of testosterone can be
used as adjuvant therapy, neoadjuvant therapy, or monotherapy
for either primary or salavage treatment. Adjuvant and
neoadjuvant hormone therapy is more common for primary
treatment. Androgen ablation and deprivation monotherapy
is more common during salvage treatment. During primary
therapy, hormone therapy is given to shrink the volume
of the prostate gland and tumor. Eventually, the prostate
cells become resistant to the androgen deprivation therapy
and begin to grow again. When prostate cells become
resistant, the next steps are either to stop hormone
therapy to see if the reintroduction of testosterone
can slow the growth, or chemotherapy.
The testicles
produce 90 percent to 95 percent of the body’s
testosterone. The adrenal glands produce the remaining
5 percent to 10 percent. The two types of hormone therapies
used to combat prostate cancer are castration or anti
– androgens. There are two types of castration:
surgical castration, also called orchiectomy or orchidectomy,
and chemical castration, caused by LHRH agonists and
LHRH antagonists. LHRH agonists and antagonists are
usually taken through injections or analogs which continuously
release the therapy over a period of time. Castration
affects production of testosterone in the testicles,
while LHRH antagonists and agonists interrupt the communication
in the brain when the brain is ordering the production
of more testosterone.
Anti –
androgens affect the hormones that are produced in the
adrenal glands. They are designed to block receptors
in the prostate cells and prevent androgens from feeding
cancer cell growth. Anti-androgens are taken orally
as a pill or tablet. The female sex hormone, estrogen
is also sometimes used for hormone therapy.
When several
hormone therapies are used together, it is called Combined
Androgen Blockade or CAB, but may also be called total
androgen blockade, combined hormonal therapy, or complete
hormonal blockade. Combined androgen blockade usually
consists of castration and anti – androgens. All
men who undergo hormone therapy will experience side
effects, however, men who undergo CAB tend to experience
more side effects due to the elimination of 100 percent
of the body’s testosterone.
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