Key Points for This Section

Avoiding risk factors and increasing protective factors may help prevent cancer. The following risk factors may increase the risk of ovarian cancer: Family history of ovarian cancer Inherited risk Hormone replacement therapy Fertility drugs Talc Obesity The following protective factors may decrease the risk of ovarian cancer: Oral contraceptives Pregnancy and breastfeeding Bilateral tubal ligation or hysterectomy Prophylactic oophorectomy Cancer prevention clinical trials are used to study ways to prevent cancer. New ways to prevent ovarian cancer are being studied in clinical trials.

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

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 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.

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 ¹ 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 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 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 ². Check for clinical trials in NCI's PDQ Cancer Clinical Trials Registry for ovarian cancer prevention trials ³ that are now accepting patients.

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

The opening of the rectum to the outside of the body.

Affecting both the right and left sides of the body.

A mass of blood that forms when blood platelets, proteins, and cells stick together. When a blood clot is attached to the wall of a blood vessel, it is called a thrombus. When it moves through the bloodstream and blocks the flow of blood in another part of the body, it is called an embolus.

A measure of the amount of minerals (mostly calcium and phosphorous) contained in a certain volume of bone. Bone density measurements are used to diagnose osteoporosis (a condition marked by decreased bone mass), to see how well osteoporosis treatments are working, and to predict how likely the bones are to break. Low bone density can occur in patients treated for cancer. Also called BMD, bone mass, and bone mineral density.

A gene on chromosome 17 that normally helps to suppress cell growth. A person who inherits certain mutations (changes) in a BRCA1 gene has a higher risk of getting breast, ovarian, prostate, and other types of cancer.

A gene on chromosome 13 that normally helps to suppress cell growth. A person who inherits certain mutations (changes) in a BRCA2 gene has a higher risk of getting breast, ovarian, prostate, and other types of cancer.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

The process by which a professional counselor helps a person cope with mental or emotional distress, and understand and solve personal problems.

The things a person eats and drinks.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

A condition in which the ovaries stop working and menstrual periods stop before age 40. Natural menopause usually occurs around age 50. A woman is said to be in menopause when she hasn’t had a period for 12 months in a row. Symptoms of menopause include hot flashes, mood swings, night sweats, vaginal dryness, trouble concentrating, and infertility. Early menopause can be caused by some cancer treatments, surgery to remove the ovaries, and certain diseases or genetic conditions. Also called premature menopause, premature ovarian failure, and primary ovarian insufficiency.

A type of hormone made by the body that helps develop and maintain female sex characteristics and the growth of long bones. Estrogens can also be made in the laboratory. They may be used as a type of birth control and to treat symptoms of menopause, menstrual disorders, osteoporosis, and other conditions.

Hormones (estrogen, progesterone, or both) given to postmenopausal women or to women who have had their ovaries surgically removed. Hormones are given to replace the estrogen no longer produced by the ovaries. Also called ERT.

A slender tube through which eggs pass from an ovary to the uterus. In the female reproductive tract, there is one ovary and one fallopian tube on each side of the uterus.

The ability to produce children.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

An inherited disorder in which affected individuals have a higher-than-normal chance of developing colorectal cancer and certain other types of cancer, often before the age of 50. Also called HNPCC and Lynch syndrome.

Hormones (estrogen, progesterone, or both) given to women after menopause to replace the hormones no longer produced by the ovaries. Also called HRT and menopausal hormone therapy.

A sudden, temporary onset of body warmth, flushing, and sweating (often associated with menopause).

Surgery to remove the uterus and, sometimes, the cervix. When the uterus and the cervix are removed, it is called a total hysterectomy. When only the uterus is removed, it is called a partial hysterectomy.

Transmitted through genes that have been passed from parents to their offspring (children).

An inherited disorder in which affected individuals have a higher-than-normal chance of developing colorectal cancer and certain other types of cancer, often before the age of 50. Also called hereditary nonpolyposis colon cancer and HNPCC.

Refers to the practices and procedures used for the prevention, treatment, or relief of symptoms of a diseases or abnormal conditions. This term may also refer to a legal drug used for the same purpose.

The time of life when a woman’s ovaries stop producing hormones and menstrual periods stop. Natural menopause usually occurs around age 50. A woman is said to be in menopause when she hasn’t had a period for 12 months in a row. Symptoms of menopause include hot flashes, mood swings, night sweats, vaginal dryness, trouble concentrating, and infertility.

In medicine, a mineral is a nutrient that is needed in small amounts to keep the body healthy. Mineral nutrients include the elements calcium, magnesium, and iron.

Having an abnormally high, unhealthy amount of body fat.

Surgery to remove one or both ovaries.

A pill used to prevent pregnancy. It contains hormones that block the release of eggs from the ovaries. Most oral contraceptives include estrogen and progestin. Also called birth control pill.

A condition that is marked by a decrease in bone mass and density, causing bones to become fragile.

Cancer that forms in tissues of the ovary (one of a pair of female reproductive glands in which the ova, or eggs, are formed). Most ovarian cancers are either ovarian epithelial carcinomas (cancer that begins in the cells on the surface of the ovary) or malignant germ cell tumors (cancer that begins in egg cells).

One of a pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus.

Being too heavy for one’s height. Excess body weight can come from fat, muscle, bone, and/or water retention. Being overweight does not always mean being obese.

The release of an egg from an ovary during the menstrual cycle.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

The area of the body between the anus and the vulva in females, and between the anus and the scrotum in males.

The tissue that lines the abdominal wall and covers most of the organs in the abdomen.

In medicine, action taken to decrease the chance of getting a disease or condition. For example, cancer prevention includes avoiding risk factors (such as smoking, obesity, lack of exercise, and radiation exposure) and increasing protective factors (such as getting regular physical activity, staying at a healthy weight, and having a healthy diet).

Any natural or laboratory-made substance that has some or all of the biologic effects of progesterone, a female hormone.

In medicine, something that prevents or protects.

Surgery intended to reduce the risk of ovarian cancer by removing the ovaries before disease develops.

Something that may decrease the chance of getting a certain disease. Some examples of protective factors for cancer are getting regular physical activity, staying at a healthy weight, and having a healthy diet.

Something that increases the chance of developing a disease. Some examples of risk factors for cancer are age, a family history of certain cancers, use of tobacco products, being exposed to radiation or certain chemicals, infection with certain viruses or bacteria, and certain genetic changes.

Sexual desire. Also called libido and sexual urge.

Adding nutrients to the diet.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A mineral, usually used in a powdered form. In cancer treatment, sterile talc is used to prevent pleural effusions (an abnormal collection of fluid in the space between the lungs and the chest wall). Talc is inserted into the space, causing it to close up, so fluid cannot collect there. Also called sterile talc powder.

A group or layer of cells that work together to perform a specific function.

An operation to tie the fallopian tubes closed. This procedure prevents pregnancy by blocking the passage of eggs from the ovaries to the uterus.

The small, hollow, pear-shaped organ in a woman's pelvis. This is the organ in which a fetus develops. Also called womb.

The muscular canal extending from the uterus to the exterior of the body. Also called birth canal.

Having to do with the vagina (the birth canal).

A nutrient that the body needs in small amounts to function and stay healthy. Sources of vitamins are plant and animal food products and dietary supplements. Some vitamins are made in the human body from food products. Vitamins are either fat-soluble (can dissolve in fats and oils) or water-soluble (can dissolve in water). Excess fat-soluble vitamins are stored in the body’s fatty tissue, but excess water-soluble vitamins are removed in the urine. Examples are vitamin A, vitamin C, and vitamin E.