Patient education: Screening for ovarian cancer (Beyond the Basics)

INTRODUCTION — Ovarian cancer is one of the deadliest cancers in women, in part because it is often found at late stage. There is a great deal of interest in finding a test or combination of tests that could detect ovarian cancer at an early, treatable stage. However, studies have not yet shown that screening tests decrease the risk of dying of ovarian cancer. Until more studies are completed:

●Women with no family history of ovarian cancer are advised to not have ovarian cancer screening unless enrolled in a clinical trial.

●Women with a "high-risk" family history of ovarian cancer are at increased risk of ovarian cancer. Women with a particularly high risk may benefit from ovarian cancer screening. (See 'High-risk family history' below.)

This article uses the word "women" to refer to people with ovaries. However, we recognize that not all people with ovaries identify as women.

This article will review the risks and benefits of screening for ovarian cancer. Diagnosis, staging, and treatment of ovarian cancer are discussed separately. (See "Patient education: Ovarian cancer diagnosis and staging (Beyond the Basics)" and "Patient education: Treatment of ovarian cancer (Beyond the Basics)".)

More detailed information about ovarian cancer screening is available by subscription. (See 'Professional level information' below.)

AM I AT RISK FOR OVARIAN CANCER? — Factors that increase your risk of ovarian cancer include the following:

●Older age

●Having one or more relatives with ovarian cancer

●Having abnormalities in certain genes, such as BRCA1 or BRCA2

●Having genes that are linked to hereditary nonpolyposis colorectal cancer (HNPCC; also called Lynch syndrome)

●Never being pregnant

●Being overweight

Some factors can reduce your risk of developing ovarian cancer, including:

●Using hormonal methods of birth control (pills, patch, vaginal ring, injection)

●Being pregnant, breastfeeding

●Having your fallopian tubes "tied" (a procedure called tubal ligation) to prevent pregnancy

●Having your uterus, fallopian tubes, or ovaries removed

RISKS AND BENEFITS OF SCREENING — A screening test is one that can find a disease, such as cancer, in the early stages when there are no symptoms and when the cancer is most likely to respond to treatment. An example of a common screening test is a colonoscopy, which is used to detect precancerous polyps and early cancers of the colon.

A screening test must find most people with the condition and not mistakenly find people who do not have the condition. A test that is positive when no disease is present is termed a "false-positive" test. It is especially important to avoid having false-positive tests for ovarian cancer, since a positive screening test usually requires surgery.

Benefits — The potential benefit of ovarian cancer screening is the chance to find the cancer at a curable stage, reducing the risk of dying.

Risks — The potential risk of ovarian cancer screening is having a false-positive screening test. This might lead to unnecessary surgery for many healthy women. Surgery carries risks including anxiety, injury, costs, and time out of work, as well as a small risk of serious complications.

SCREENING TESTS FOR HIGH-RISK WOMEN — Studies are being done to find the best combination of screening tests for ovarian cancer. Tests that may be useful for women at high risk of ovarian cancer include a blood test of the CA 125 tumor marker, ultrasound, or a combination of the two.

CA 125 tumor marker — CA 125 is a protein that is higher than normal in approximately 80 percent of women with ovarian cancer. It can be measured with a blood test. CA 125 is commonly used to monitor women with ovarian cancer.

It was hoped that CA 125 could be used to know if a woman was at risk for ovarian cancer. However, CA 125 levels can be high with a variety of other conditions, including:

●Endometriosis

●Uterine fibroids

●Liver disease (cirrhosis)

●Pelvic infections

●Other cancers, including endometrial, breast, lung, and pancreatic cancer.

Also, CA 125 levels are higher than normal in about 1 percent of healthy women, and the levels can change during the menstrual cycle.

So if you have a higher than normal CA 125 level, you could have ovarian cancer or a just a more common (and less serious) condition. As a result, CA 125 is not recommended as a standalone screening test for ovarian cancer.

Pelvic ultrasound — Pelvic ultrasound uses sound waves to create an image of the organs in the pelvis, including the ovaries. The test usually involves using an ultrasound wand placed on the outside of the abdomen and inside the vagina.

When used as a screening test for ovarian cancer, vaginal ultrasound can find between 80 and 100 percent of ovarian cancers. However, ultrasound cannot always tell the difference between ovarian cancer and other more common conditions (ovarian cyst, endometriosis). False-positive ultrasound tests (abnormal tests in the absence of a cancer) may lead to more testing or unnecessary surgery to further evaluate the ovary. As a result, pelvic ultrasound is not recommended as a standalone screening test for ovarian cancer.

Combined CA 125 and pelvic ultrasound — Several studies have looked at using CA 125 and pelvic ultrasound together to detect ovarian cancer. However, the results of these studies have been somewhat disappointing:

●Many women had unnecessary surgery because of false-positive test results (the CA 125 or pelvic ultrasound was abnormal but no cancer was found).

●Some studies of CA 125 and pelvic ultrasound have found more cancers at an early, more treatable stage, while others have not. No published studies have shown that these tests reduce the risk of dying of ovarian cancer.

WHO SHOULD BE SCREENED?

High-risk family history — A woman with a "high-risk" family history is someone who has a strong family history of breast or ovarian cancer in more than one relative or has family members with cancer who have certain characteristics.

Women with this history should meet with a genetic counselor to discuss genetic testing for BRCA1 and BRCA2 (table 1). Genetic testing is discussed in a separate article. (See "Patient education: Genetic testing for hereditary breast, ovarian, prostate, and pancreatic cancer (Beyond the Basics)".)

Ovarian cancer screening may be recommended if you have a high-risk family history of ovarian cancer and:

●You have a BRCA 1 or 2 mutation and you have ovaries

●You have Lynch syndrome (also called hereditary nonpolyposis colorectal cancer [HNPCC]) and you have ovaries

Ovarian cancer screening may also be considered for women who are eligible to have genetic testing (because of their high-risk family history) but who have chosen not to have genetic testing. In this group, ovarian cancer screening may be recommended, starting at age 30 to 35, or 5 to 10 years earlier than the age when the youngest family member was diagnosed. Screening may include a blood test for CA 125 and a pelvic ultrasound.

If you have a high risk family history, there are alternatives to ovarian cancer screening, such as having your ovaries removed to prevent cancer. These options are discussed separately. (See "Patient education: Genetic testing for hereditary breast, ovarian, prostate, and pancreatic cancer (Beyond the Basics)", section on 'Interpreting the results'.)

Lower-risk family history — Women who do not meet the criteria for a high-risk family history should discuss their risks for ovarian cancer with a health care provider. Ovarian cancer screening is not usually recommended for this group.

Average-risk women — Women with an "average risk" of ovarian cancer do not have a personal or family history of ovarian cancer. Screening for ovarian cancer is not recommended in average-risk women.

SYMPTOMS OF OVARIAN CANCER — During the early stages of ovarian cancer, symptoms are often vague and ill-defined. Symptoms may include pelvic or abdominal discomfort, bloating, difficulty eating or feeling full, increased abdominal size, or rushing to urinate frequently. However, these symptoms can also be caused by many other conditions.

If you have developed one or more of these symptoms in the past year, see your doctor or nurse. (See "Patient education: Ovarian cancer diagnosis and staging (Beyond the Basics)" and "Early detection of epithelial ovarian cancer: Role of symptom recognition".)

WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Ovarian cancer screening (The Basics)
Patient education: Ovarian cancer (The Basics)
Patient education: Cancer screening (The Basics)
Patient education: Ovarian cysts (The Basics)
Patient education: Genetic testing for breast, ovarian, prostate, and pancreatic cancer (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient education: Ovarian cancer diagnosis and staging (Beyond the Basics)
Patient education: Treatment of ovarian cancer (Beyond the Basics)
Patient education: Genetic testing for hereditary breast, ovarian, prostate, and pancreatic cancer (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Early detection of epithelial ovarian cancer: Role of symptom recognition
Genetic testing and management of individuals at risk of hereditary breast and ovarian cancer syndromes
Cancer risks and management of BRCA1/2 carriers without cancer
Screening for ovarian cancer

The following organizations also provide reliable health information.

●National Cancer Institute

●Medline Plus (available in Spanish)

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