Most women have one or more risk factors for ovarian cancer. However, most of the common factors only slightly increase your risk, so they only partly explain the frequency of the disease. So far, knowledge about risk factors has not been translated into practical ways to prevent most cases of ovarian cancer.

There are several ways you can reduce your risk of developing epithelial ovarian cancer. Much less is known about ways to lower the risk of developing germ cell and stromal tumors of the ovaries. The remainder of this section refers to epithelial ovarian cancer only. It is important to realize that some of these strategies reduce the risk only slightly, while others decrease it much more. Some strategies are easily followed, and others require surgery. If you are concerned about your risk of ovarian cancer, you may want to discuss this information with your health care professionals. They can help you consider these ideas in the context of your own situation.

Oral contraceptives: The use of oral contraceptives (birth control pills) decreases the risk of developing ovarian cancer, especially among women who use them for several years. Compared with women who never used oral contraceptives, those who used oral contraceptives for 3 or more years have about a 30-50% lower risk of developing ovarian cancer.

Recent research suggests that contraceptives reduce risk in women who have mutations of the BRCA1 and BRCA2 genes. But this is not certain, as some studies have shown no decrease in risk.

Tubal ligation or hysterectomy: Tubal ligation is a surgical procedure to "tie" the fallopian tubes to prevent pregnancy. When performed after childbearing, tubal ligation may reduce the chance of developing ovarian cancer by up to 67%. A hysterectomy may also reduce your risk.

Tubal ligation has also been shown to be effective in reducing the risk of ovarian cancer in women who have the BRCA1 mutation. It is not certain if it will decrease the risk for women with the BRCA2 mutation.

No one knows for certain why tubal ligation and hysterectomy decrease the risk of ovarian cancer. One theory is that some cancer-causing substances may enter the body through the vagina and pass through the uterus and fallopian tubes to reach the ovaries. This may explain the effect on ovarian cancer risk of removing the uterus or blocking the fallopian tubes.

We emphasize that these operations should be done only when there are valid medical reasons and not exclusively for their effect on ovarian cancer risk.

If you are having a hysterectomy (removal of the uterus) for a valid medical reason and you have a strong family history of ovarian or breast cancer, you may wish to consider having both ovaries removed (bilateral oophorectomy) as part of that procedure.

If you have been through menopause (postmenopausal) or are near menopause (perimenopausal), the ovaries should be removed at the same time as the hysterectomy even if you do not have an increased risk of ovarian cancer. If you are having a hysterectomy and are older than 40, you should discuss having your ovaries removed with your doctor.

Pregnancy and breast-feeding: Having one or more children, plus prolonged (one year or more) breast-feeding, also may decrease your risk. Although it has been thought that having children early helps to reduce risk, a recent study also shows even lower risk of ovarian cancer in women who have their children after age 35. Although these measures slightly reduce risk, they do not guarantee protection against ovarian cancer. Doctors do not recommend making choices about when to have a child specifically for the purpose of reducing ovarian cancer risk, especially since using oral contraceptives will have a greater impact on this risk.

Diet: A number of studies have shown a reduced rate of ovarian cancer in women who ate a diet high in vegetables. The American Cancer Society recommends eating a variety of healthful foods, with an emphasis on plant sources. Eat at least five servings of fruits and vegetables every day, as well as servings of whole grain foods from plant sources such as breads, cereals, grain products, rice, pasta, or beans. Eat fewer red meats, especially those high in fat or processed. Even though the impact of these dietary recommendations on ovarian cancer risk remains uncertain, following these recommendations can help prevent several other diseases, including some other types of cancer.

Analgesics: In some studies, both aspirin and acetaminophen have been shown to reduce the risk of ovarian cancer. However, the information is not consistent, and women should not take these medicines regularly to prevent ovarian cancer. More research is needed on this issue.

Genetic counseling can predict whether you are likely to have one of the gene mutations associated with an increased ovarian cancer risk. If your family history suggests that you might have one of these gene mutations, genetic testing can be done.

Before having genetic tests, you should discuss their benefits and potential drawbacks. Genetic testing can determine if you or members of your family carry certain gene mutations that cause a high risk of ovarian cancer. For some women with a strong family history of ovarian cancer, knowing they do not have a mutation that increases their ovarian cancer risk can be a great relief for them and their children. Knowing that you do have such a mutation can be stressful, but many women find this information very helpful in making important decisions about certain prevention strategies for them and their children.

Use of oral contraceptives is one way that women at average risk of developing ovarian cancer can reduce their risk for this disease. They may also reduce the risk for women with BRCA1 and BRCA2 mutations, but this is not certain. Also, some studies have indicated that oral contraceptives might increase your breast cancer risk if you have a strong family history of breast cancer. Other studies have not found any increase in breast cancer risk among women with BRCA mutations who take oral contraceptives. Additional research is needed to find out more about the risks and benefits of oral contraceptives for women at high ovarian and breast cancer risk.

Surgery to remove one or both ovaries is called an oophorectomy. A prophylactic oophorectomy is surgery to remove both of the ovaries before an ovarian cancer occurs. This is a controversial operation because it causes premature menopause in premenopausal women and may be unnecessary. Generally, it is recommended only for certain very high-risk patients over age 40. This operation lowers ovarian cancer risk a great deal but does not entirely eliminate it. Women can still develop cancer involving the peritoneum.

Women at high risk of ovarian cancer who are having their ovaries removed should also have their fallopian tubes completely removed.

Recent research showed that women who have BRCA gene mutations and have their ovaries removed have a substantial reduction in their risk of ovarian and breast cancers. In one study, 98% of these women were free of ovarian or primary peritoneal cancer at 5 years, and 94% were free of breast cancer. In the other study, the risk of ovarian cancer in BRCA positive women who had prophylactic oophorectomy was reduced 85% and the risk of breast cancer was reduced 25%.

Revised: 09/08/2004