Hormone Therapy for Cancer Treatment
What is hormone therapy?
Hormones are chemicals made by glands, such as the ovaries and testicles. Hormones
help some types of cancer cells grow, such as breast cancer and prostate cancer. In
other cases, hormones can kill cancer cells, make cancer cells grow more slowly, or
stop them from growing. Hormone therapy as a cancer treatment may involve taking medications
that interfere with the activity of the hormone or stop the body's production of the
hormone. Hormone therapy may involve surgically removing a gland that is producing
How does hormone therapy work?
If you have breast cancer, your doctor may recommend a hormone receptor test of the
tumor to help determine treatment options and help learn more about the tumor. This
test can help to predict whether the cancer cells are sensitive to hormones.
The hormone receptor test measures the amount of certain proteins (called hormone
receptors) in cancer tissue. Hormones that naturally occur in the body (such as estrogen
and progesterone) can attach to these proteins and help them grow. If the test is
positive, it is indicating that the hormone is probably helping the cancer cells to
grow. In this case, hormone therapy may be given to block the way the hormone works
and help keep the hormone away from the cancer cells (hormone receptors). If the test
is negative, the hormone does not affect the growth of the cancer cells, and other
effective cancer treatments may be given. Always discuss the results of the hormone
receptor test with your doctor.
If the test indicates that the hormones are affecting your cancer, the cancer may
be treated in one of following ways:
Treating cancer cells to block the hormones they need to grow
Treating the glands that produce hormones to keep them from making hormones
Surgery to remove glands that produce the hormones, such as the ovaries that produce
estrogen, or the testicles that produce testosterone
The type of hormone therapy a person receives depends on many factors, such as the
type and size of the tumor, the age of the person, the presence of hormone receptors
on the tumor, and other factors.
When is hormone therapy given?
Your doctor may prescribe hormone therapies before some cancer treatments or after
other cancer treatments. If hormone therapy is given before the primary treatment,
it is called neoadjuvant treatment. Neoadjuvant treatments help to kill cancer cells
and contribute to the effectiveness of the primary therapy, which is usually surgery.
If hormone therapy is given after the primary cancer treatment, it is called adjuvant
treatment. Adjuvant therapy is given to improve the chance of a cure.
With some cancers, hormone therapy is given as soon as cancer is diagnosed, and before
any other treatment. It may shrink a tumor or it may halt the advance of the disease.
And in some cancers, such as prostate cancer, it is helpful in relieve the painful
and distressing symptoms of advanced disease. Although hormone therapy cannot cure
advanced prostate cancer, it will usually shrink or halt the advance of disease, often
What medications are used for hormone therapy?
Hormone therapy may be used to prevent the growth, spread, and recurrence of breast
cancer. The female hormone estrogen can increase the growth of breast cancer cells
in some women. An example of this type of medication is tamoxifen, which works by
blocking the effects of estrogen on the growth of malignant cells in breast tissue.
However, tamoxifen does not stop the production of estrogen. Men who have breast cancer
may also be treated with tamoxifen.
Tamoxifen is currently being studied as a hormone therapy for treatment of other types
of cancer. There are several other hormonal agents for breast cancer that target the
estrogen receptor like tamoxifen, including toremifene (Fareston) and fulvestrant
Hormone therapy may be considered for women whose breast cancers test positive for
estrogen or progesterone receptors.
Newer medications approved by the FDA, called aromatase inhibitors, are used to treat
advanced breast cancer or prevent the recurrence of breast cancer in postmenopausal
women. These drugs, such as anastrozole (Arimidex), letrozole (Femara), and exemestane
(Aromasin), prevent estrogen production in postmenopausal women, and may be the drug
of choice for women who are past menopause.
The FDA approved the use of raloxifene (Evista) for postmenopausal women who are at
high risk for breast cancer. It is also prescribed for women who have osteoporosis.
Raloxifene is not for use in premenopausal women. It now joins tamoxifen as another
drug that can be used to help at-risk women lower their risk of invasive breast cancer.
Fulvestrant (Faslodex), also approved by the FDA, binds with the estrogen receptor
and eliminates it, rather than than just blocking it, making estrogen less effective
in promoting growth of the cancer.
With prostate cancer, there may be a variety of medications used in hormone therapy.
Male hormones, such as testosterone, stimulate prostate cancer to grow. Hormone therapy
is given to help stop hormone production and to block the activity of the male hormones.
Hormone therapy can cause a tumor to shrink and the prostate-specific antigen levels
What are the side effects of hormone therapy?
The following are some potential side effects that may occur with hormone therapy.
However, the side effects will vary depending on the type of hormone therapy that
is given. Every person's hormone treatment experience is different and not every person
will experience the same side effects. Discuss the potential side effects of your
hormone therapy with your doctor.
As each person's individual medical profile and diagnosis is different, so is his
or her reaction to treatment. Side effects may be severe, mild, or absent. Be sure
to discuss possible side effects of treatment with your cancer care team before the
For prostate cancer, either the surgical removal of the testes or hormone drug therapy
can improve the cancer. Both surgery and drugs may cause the following side effects:
For breast cancer, some women may experience side effects from tamoxifen that are
similar to the symptoms some women experience in menopause. Other women do not experience
any side effects when taking tamoxifen. The following are some of the side effects
that may occur when taking tamoxifen:
Nausea and/or vomiting
Vaginal spotting (a blood-stained discharge from the vagina that is not part of the
regular menstrual cycle)
Irregular menstrual periods
Vaginal dryness or itching and/or irritation of the skin around the vagina
Taking tamoxifen also slightly increases the risk of endometrial cancer (cancer of the
lining of the uterus) and uterine sarcoma (cancer of the muscular wall of the uterus).
There is also a very small risk of blood clots and stroke, eye problems such as cataracts,
and liver toxicities. Tamoxifen should be avoided during pregnancy.