Avoiding risk factors and increasing protective factors may help prevent
Avoiding cancer risk factors such as smoking, being overweight, and lack of
exercise may help prevent certain cancers. Increasing protective factors such as
quitting smoking, eating a healthy diet, and exercising may also help prevent
some cancers. Talk to your doctor or other health care professional about how
you might lower your risk of cancer.
The following risk factors may increase the risk of endometrial cancer:
Estrogen is a hormone made by the body. It helps the body develop and
maintain female sex characteristics. Estrogen can affect the growth of some
cancers, including endometrial cancer. A woman's risk of developing endometrial
cancer is increased by being exposed to estrogen in the following ways:
- Estrogen-only hormone replacement therapy: Estrogen may be given to
replace the estrogen no longer produced by the ovaries in postmenopausal
women or women whose ovaries have been removed. This is called hormone
replacement therapy (HRT), or hormone therapy (HT). The use of hormone
replacement therapy that contains only estrogen increases the risk of
endometrial cancer. For this reason, estrogen therapy alone is usually
prescribed only for women who do not have a uterus.
When estrogen is combined with progestin (another hormone), it is called
combination estrogen-progestin replacement therapy. For postmenopausal
women, taking estrogen in combination with progestin does not increase the
risk of endometrial cancer.
- Early menstruation: Beginning to have menstrual periods at an early age
increases the number of years the body is exposed to estrogen and increases
a woman's risk of endometrial cancer.
- Late menopause: Women who reach menopause at an older age are exposed to
estrogen for a longer time and have an increased risk of endometrial cancer.
- Never being pregnant: Because estrogen levels are lower during
pregnancy, women who have never been pregnant are exposed to estrogen for a
longer time than women who have been pregnant. This increases the risk of
Tamoxifen is one of a group of drugs called selective estrogen receptor
modulators, or SERMs. Tamoxifen acts like estrogen on some tissues in the body,
such as the uterus, but blocks the effects of estrogen on other tissues, such as
the breast. When tamoxifen is used to prevent breast cancer in women who are at
high risk for the disease, it increases the risk of endometrial cancer. This
risk is greater in postmenopausal women.
Raloxifene is a SERM that is used to prevent bone weakness in postmenopausal
women. It does not have estrogen-like effects on the uterus and has not been
shown to increase the risk of endometrial cancer. Other SERMs are being studied
in clinical trials.
Hereditary nonpolyposis colon cancer (HNPCC) syndrome is an inherited
disorder caused by changes in certain genes. Women who have HNPCC syndrome have
a much higher risk of developing endometrial cancer than women who do not have
Polycystic ovary syndrome
Women who have polycystic ovary syndrome (a disorder of the hormones made by
the ovaries) have an increased risk of endometrial cancer.
Obesity increases the risk of endometrial cancer. This may be because obesity
is related to other risk factors such as estrogen levels, polycystic ovary
syndrome, lack of physical activity, and a diet that is high in saturated fats.
It is not known if losing weight decreases the risk of endometrial cancer.
The following protective factors may decrease the risk of endometrial
Combination oral contraceptives
Taking contraceptives that combine estrogen and progestin (combination oral
contraceptives) decreases the risk of endometrial cancer. The protective effect
of combination oral contraceptives increases with the length of time they are
used, and can last for many years after oral contraceptive use has been stopped.
Physical activity may lower the risk of endometrial cancer.
Pregnancy and breast-feeding
Estrogen levels are lower during pregnancy and when breast-feeding. Being
pregnant and/or breast-feeding may lower the risk of endometrial cancer.
A diet low in saturated fats and high in fruits and vegetables may lower the
risk of endometrial cancer. The risk may also be lowered when soy -based foods
are a regular part of the diet.
Cancer prevention clinical trials are used to study ways to prevent
Cancer prevention clinical trials are used to study ways to lower the risk of
developing certain types of cancer. Some cancer prevention trials are conducted
with healthy people who have not had cancer but who have an increased risk for
cancer. Other prevention trials are conducted with people who have had cancer
and are trying to prevent another cancer of the same type or to lower their
chance of developing a new type of cancer. Other trials are done with healthy
volunteers who are not known to have any risk factors for cancer.
The purpose of some cancer prevention clinical trials is to find out whether
actions people take can prevent cancer. These may include eating fruits and
vegetables, exercising, quitting smoking, or taking certain medicines, vitamins,
minerals, or food supplements.