Risk Factors of Ovarian Cancer

As with many types of cancer, there are some factors known to increase and decrease the risk of developing ovarian cancer. If ovarian cancer runs in your family, you are more likely to develop the disease, but there are other procedures and factors that may put you at risk. It is important to understand the risks and speak with your doctor about any health concerns you have. The National Cancer Institute has outlined some of these factors:

Avoiding risk factors and increasing protective factors may help prevent cancer.

Avoiding cancer risk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. 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 ovarian cancer:

Family history of ovarian 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.

Inherited risk

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

BRCA1 or BRCA2 genes.

Genes that are linked to hereditary nonpolyposis colorectal cancer (HNPCC; Lynch syndrome).

Hormone replacement therapy

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.

Fertility drugs

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

Talc

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.

Obesity

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.

Height

Being taller than 5 feet 8 inches is linked to an increased risk of ovarian cancer.

The following protective factors may decrease the risk of ovarian cancer:

Oral contraceptives

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

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.

Bilateral tubal ligation or hysterectomy

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).

Prophylactic oophorectomy

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:

Hot flashes.

Night sweats.

Trouble sleeping.

Mood changes.

Decreased sex drive.

Heart disease.

Vaginal dryness.

Osteoporosis (decreased bone density).

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 oophorectomycontinue 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 prevent cancer.

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.

New ways to prevent ovarian cancer are being studied in clinical trials.

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 NCI's list of cancer clinical trials for ovarian cancer prevention trials that are now accepting patients.

If you think you may be at risk for ovarian cancer, speak with your gynecologist.