- About Screening
- Screening Tests
- Screening Risks
Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage. When abnormal tissue or cancer is found early, it may be easier to treat. By the time symptoms appear, cancer may have begun to spread.
Scientists are trying to better understand which people are more likely to get certain types of cancer. They also study the things we do and the things around us to see if they cause cancer. This information helps doctors recommend who should be screened for cancer, which screening tests should be used, and how often the tests should be done.
It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms.
If a screening test result is abnormal, you may need to have more tests done to find out if you have cancer. These are called diagnostic tests.
Refer to the following PDQ summaries for information about prevention, diagnosis, and treatment of ovarian cancer:
- Prevention of Ovarian Cancer
- Genetics of Breast and Ovarian Cancer
- Ovarian Epithelial Cancer Treatment
- Ovarian Germ Cell Tumors Treatment
- Ovarian Low Malignant Potential Tumors Treatment
Ovarian cancer is a disease in which malignant (cancer) cells form in the tissues of the ovaries.
The ovaries are a pair of organs in the female reproductive system. They are located 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 produce eggs and female hormones (chemicals that control the way certain cells or organs function).
In the United States, ovarian cancer is the fifth leading cause of cancer death in women.
Ovarian cancer is also the leading cause of death from cancer of the female reproductive system. From 1987 through 2002 the number of ovarian cancer cases went down slightly and the number of deaths from ovarian cancer remained about the same. Current screening tests have not been proven to decrease the death rate.
Age and a family history of ovarian cancer can affect the risk of developing ovarian cancer.
Anything that increases your chance of getting a disease is called a risk factor. Risk factors for ovarian cancer include the following:
- Being older.
- Having a family history of ovarian cancer.
- Taking hormone replacement therapy after menopause.
- Using fertility drugs.
- Having increased levels of CA 125.
- Having certain hereditary conditions, such as hereditary nonpolyposis colon cancer (HNPCC), also called Lynch Syndrome.
Certain factors may decrease a woman's risk of developing ovarian cancer. Women who have taken oral contraceptives ("the pill"), given birth, breast-fed, or had a tubal ligation or hysterectomy have a lower than average risk of developing ovarian cancer. Prophylactic oophorectomy (removal of healthy ovaries) decreases ovarian cancer risk in women who have an altered gene related to breast cancer.
Tests are used to screen for different types of cancer.
Some screening tests are used because they have been shown to be helpful both in finding cancers early and in decreasing the chance of dying from these cancers. Other tests are used because they have been shown to find cancer in some people; however, it has not been proven in clinical trials that use of these tests will decrease the risk of dying from cancer.
Scientists study screening tests to find those with the fewest risks and most benefits. Cancer screening trials also are meant to show whether early detection (finding cancer before it causes symptoms) decreases a person's chance of dying from the disease. For some types of cancer, finding and treating the disease at an early stage may result in a better chance of recovery.
There is no standard or routine screening test for ovarian cancer.
Screening for ovarian cancer is under study and there are screening clinical trials taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site.
Tests that may detect (find) ovarian cancer are being studied:
A pelvic exam is an exam of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum. The doctor or nurse inserts one or two lubricated, gloved fingers of one hand into the vagina and the other hand is placed over the lower abdomen to feel the size, shape, and position of the uterus and ovaries. A speculum is also inserted into the vagina and the doctor or nurse looks at the vagina and cervix for signs of disease.
Ovarian cancer is usually advanced when detected by a pelvic exam.
Transvaginal ultrasound is a procedure used to examine the vagina, uterus, fallopian tubes, and bladder. An ultrasound transducer (probe) is inserted into the vagina and used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram.
A CA 125 assay is a test that measures the level of CA 125 in the blood. CA 125 is a substance released by cells into the bloodstream. An increased CA-125 level is sometimes a sign of certain types of cancer, including ovarian cancer, or other conditions.
Scientists at the National Cancer Institute are studying the combination of ultrasound and CA-125 levels as a way to get more accurate results from the screening tests.
Screening tests have risks.
Decisions about screening tests can be difficult. Not all screening tests are helpful and most have risks. Before having any screening test, you may want to discuss the test with your doctor. It is important to know the risks of the test and whether it has been proven to reduce the risk of dying from cancer.
The risks of ovarian screening tests include the following: Finding ovarian cancer may not improve health or help a woman live longer.
Screening may not improve your health or help you live longer if you have advanced ovarian cancer or if it has already spread to other places in your body.
Some cancers never cause symptoms or become life-threatening, but if found by a screening test, the cancer may be treated. It is not known if treatment of these cancers would help you live longer than if no treatment were given, and treatments for cancer may have serious side effects.
False-negative test results can occur.
Screening test results may appear to be normal even though ovarian cancer is present. A woman who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if she has symptoms.
False-positive test results can occur.
Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests (such as a laparoscopy or a laparotomy to see if cancer is present), which also have risks. An unnecessary oophorectomy (removal of one or both ovaries) may also result.
Your doctor can advise you about your risk for ovarian cancer and your need for screening tests.