Ovarian Cancer Prevention (PDQ®)

As a National Cancer Institute (NCI)-designated Comprehensive Cancer Center, a core part of our mission is to educate patients and the community about cancer. The following summary is trusted information from the NCI.

What is prevention?

Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.

To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.

Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.

Different ways to prevent cancer are being studied, including:

  • Changing lifestyle or eating habits.
  • Avoiding things known to cause cancer.
  • Taking medicines to treat a precancerous condition or to keep cancer from starting.

General Information About Ovarian Cancer

The ovaries are a pair of organs in the female reproductive system. They are in the pelvis, one on each side of the uterus (the hollow, pear-shaped organ where a fetus grows). Each ovary is about the size and shape of an almond. The ovaries make eggs and female hormones (chemicals that control the way certain cells or organs work in the body).Anatomy of the female reproductive system. The organs in the female reproductive system include the uterus, ovaries, fallopian tubes, cervix, and vagina. The uterus has a muscular outer layer called the myometrium and an inner lining called the endometrium.

Since 1992, the number of new cases of ovarian cancer has gone down slightly. The number of deaths from ovarian cancer has slightly decreased since 2002.

It is hard to find ovarian cancer early. Early ovarian cancer may not cause any symptoms. When symptoms do appear, ovarian cancer is often advanced.

See the following PDQ summaries for more information about ovarian cancer:

Ovarian Cancer Prevention

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.

A woman whose mother or sister had ovarian cancer has an increased risk of ovarian cancer. A woman with two or more relatives with ovarian cancer also has an increased risk of ovarian cancer.

The risk of ovarian cancer is increased in women who have inherited certain changes in the following genes:

The use of estrogen-only hormone replacement therapy (HRT) after menopause increases the risk of ovarian cancer. The longer estrogen replacement therapy is used, the greater the risk may be. It is not clear whether the risk of ovarian cancer is increased with the use of HRT that has both estrogen and progestin.

The use of fertility drugs may be linked to an increased risk of ovarian cancer.

The use of talc may increase the risk of ovarian cancer. Talcum powder dusted on the perineum (the area between the vagina and the anus) may reach the ovaries by entering the vagina.

Having too much body fat, especially during the teenage years, is linked to an increased risk of ovarian cancer. Being obese is linked to an increased risk of death from ovarian cancer.

The use of oral contraceptives ("the pill") lowers ovarian cancer risk. The longer oral contraceptives are used, the lower the risk may be. The decrease in risk may last up to 25 years after a woman has stopped using oral contraceptives.

Taking oral contraceptives increases the risk of blood clots. This risk is higher in women who also smoke. There may be a slight increase in a woman's risk of breast cancer during the time she is taking oral contraceptives. This risk decreases over time.

Pregnancy and breastfeeding are linked to a decreased risk of ovarian cancer. Ovulation stops or occurs less often in women who are pregnant or breastfeeding. Some experts believe that women who ovulate less often have a decreased risk of ovarian cancer.

The risk of ovarian cancer is decreased in women who have a bilateral tubal ligation (surgery to close both fallopian tubes) or a hysterectomy (surgery to remove the uterus).

Some women who have a high risk of ovarian cancer may choose to have a prophylactic oophorectomy (surgery to remove both ovaries when there are no signs of cancer). This includes women who have inherited certain changes in the BRCA1 and BRCA2 genes or in the genes linked to hereditary nonpolyposis colon cancer (HNPCC). (See the PDQ summary on Genetics of Breast and Ovarian Cancer for more information.)

It is very important to have a cancer risk assessment and counseling before making this decision. These and other factors should be discussed:

  • Early menopause: The drop in estrogen levels caused by removing the ovaries can cause early menopause. Symptoms of menopause include the following: These symptoms may not be the same in all women. Hormone replacement therapy (HRT) may be needed to lessen these symptoms.
  • Risk of ovarian cancer in the peritoneum: Women who have had a prophylactic oophorectomy continue to have a small risk of ovarian cancer in the peritoneum (thin layer of tissue that lines the inside of the abdomen). This may occur if ovarian cancer cells had already spread to the peritoneum before the surgery or if some ovarian tissue remains after surgery.

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.

Clinical trials are taking place in many parts of the country. Information about clinical trials can be found in the Clinical Trials section of the NCI Web site. Check for clinical trials in NCI's PDQ Cancer Clinical Trials Registry for ovarian cancer prevention trials that are now accepting patients.