Ovarian Cancer; Diagnosis

NWHRC Health Center - Ovarian Cancer, May 30, 2006

Who gets ovarian cancer? A woman can inherit an increased risk for this disease, particularly if a "first degree" relative (a mother, sister or daughter) has or had ovarian, breast or colon cancer. In fact, if a woman has a strong family history of ovarian cancer, she is more likely to develop the disease at an early age (younger than 50). Other risk factors include:

Being of Eastern European Jewish ethnicity (Askhenazi) if the condition has already affected one or more family members

Having a mutation in the BRCA1 or BRCA2 gene. A mutation in the BRCA1 or BRCA2 gene increases your risk by an estimated 40 to 50 percent.

Having a personal history of breast, endometrial or colon cancer

Never having been pregnant or having your first child after age 30.

A high-fat diet

Obesity

Starting your periods at a young age, or going through menopause at an older than average age

Of all risk factors, the most significant is a family history of breast and/or ovarian cancer. However, it's important to keep risk factors in perspective. Most women with risk factors for ovarian cancer will never actually get ovarian cancer. And most women with ovarian cancer do not have any strong risk factors for the disease.

Even with significant risk factors such as family history, the overall chances of getting ovarian cancer are still small. Nonetheless, you should talk to your health care professional if you know you have any risk factors.

To date, only about nine percent of ovarian cancer cases are caused by inherited defects in the BRCA1 and BRCA2 genes. Genes, the pieces of the chemical DNA within your cells that are inherited from your parents, determine many aspects of your body's make up. Scientists have known for years that genes determine the risk for developing a disease like cancer.

The BRCA1 and BRCA2 genes normally help prevent cancer by making a protein that keeps cells from growing too much. But if you have a defect in either of these genes--inherited from either parent--they don't make that protein, and there's nothing to slow down or stop rapidly multiplying cells from becoming cancerous.

There are many questions around genetic testing for a genetic risk for ovarian cancer, both scientific and ethical.

If you want to have genetic testing, you should see a specially trained genetic counselor who can accurately and appropriately counsel you about your risk and options.

The genetic counselor, in concert with your physician, can recommend prevention and screening strategies, discuss your options for risk reduction and counsel you about the psychosocial issues around this topic, regardless of family history or inherited susceptibility. Your health care professional can refer you to a certified genetic counselor.

Diagnostic Tests

If you or your doctor suspects you may have ovarian cancer, or you have a very high risk of developing it, you will undergo certain diagnostic tests. Unfortunately, there are no screening tests for ovarian cancer (as there are for other cancers, like breast cancer or colon cancer). The following imaging tests can show whether a mass is present, but cannot tell whether or not the mass is cancerous. The CA-125 blood test is usually used in women who have already been diagnosed with ovarian cancer. Diagnostic tests include:

Abdominal or transvaginal ultrasound. This test uses sound waves to distinguish fluid-filled cysts from solid ones. It is often used to rule out or identify a possible cancer.

CT scan. This test produces x-ray images of cross sections of body tissues. It is used to show the size of the tumor or mass, whether lymph nodes are involved and whether the tumor has spread to other organs. They are also used to guide a biopsy needle into a tumor to obtain a tissue sample.

lower GI series (barium dye enema). During a barium dye enema, barium sulfate, a chalky substance, is placed into the colon and rectum. The barium outlines the colon and rectum so they are more visible on x-rays. This test enables your health professional to see the bowel on x-ray to detect abnormalities related to ovarian cancer.

CA-125 blood test. This is most commonly used in women who have already been diagnosed with ovarian cancer and treated to determine if the cancer has recurred. It measures levels of a tumor marker, or protein, called CA-125.

It is not used for screening or diagnosis because it results in too many false positives or negatives. For example, studies find that CA-125 levels are normal when ovarian cancer is confined to the ovaries in half of postmenopausal women, while some ovarian cancers do not produce enough CA-125 to cause a positive result. Other benign conditions may increase CA-125 levels, such as endometriosis, benign ovarian cysts, pelvic inflammatory disease, the first trimester of pregnancy and cirrhosis of the liver.

Future screening tests

Researchers are evaluating new methods that use the fledgling science of proteomics (the study of the proteins that govern every biological process in the body) to identify ovarian cancer in its earliest stages. Once perfected, proteomics could use protein fingerprinting to identify Stage 1 ovarian cancer from just a few drops of blood in a 30-minute test.