Blood test for ovarian cancer may be 99 accurate

If you do have symptoms and your doctor suspects you have ovarian cancer, you may have some of the tests and scans described below.

Waiting for the test results can be a stressful time. It may help to talk to a friend or family member, a health professional, or call Cancer Council 13 11 20.

Learn more about:

• Pelvic examination
• Blood tests
• Imaging scans
• Taking a biopsy
• Genetic testing after diagnosis

Pelvic examination

In a pelvic examination, the doctor will press gently on different parts of the outside of your abdomen (belly) to feel for any masses or lumps. To check your uterus and ovaries, the doctor will place two gloved fingers into your vagina while pressing on your abdomen with their other hand. You may also have a vaginal examination using an instrument that gently separates the walls of the vagina.

A pelvic examination is not painful but it may be uncomfortable. There might be another health professional in the room or, if there isn’t, you can ask for a staff member or a family member or friend to be present during the examination if you prefer.

The doctor may also perform a digital rectal examination, placing a gloved finger into the anus and rectum. This lets the doctor feel the tissue behind the uterus where cancer cells may grow.

Screening tests look for some types of cancer in people who do not have any symptoms. At present, there is no effective screening test for ovarian cancer. The cervical screening test (which replaced the Pap test in 2017) looks for human papillomavirus (HPV). This virus causes most cases of cervical cancer but not ovarian cancer. Neither the cervical screening test nor the Pap test can help find ovarian cancer.

Blood tests

You may have blood tests to check for proteins produced by cancer cells. These proteins are called tumour markers. The most common tumour marker for ovarian cancer is CA125. The level of CA125 may be higher in some cases of ovarian cancer. It can also rise for reasons other than cancer, including ovulation, menstruation, irritable bowel syndrome, liver or kidney disease, endometriosis or fibroids.

The CA125 blood test is not used to screen for ovarian cancer if you do not have any symptoms. It can be used in the following ways:

At diagnosis –A CA125 test is more accurate in diagnosing ovarian cancer if you have been through menopause. If you have early-stage ovarian cancer, CA125 levels are often normal. This is why doctors will often combine CA125 tests with an ultrasound.

During treatment –For ovarian cancer that produces CA125, the blood test may be one way to check how well treatment is working. Falling CA125 levels may mean it is working, and rising CA125 levels may mean the treatment is not working well.

After treatment –CA125 blood tests are sometimes included in follow-up tests.

Imaging scans

Your doctor may recommend a number of imaging scans to look for any pelvic mass, but they don’t confirm if any mass found is cancer. Imaging scans can also work out how far the cancer has spread.

Pelvic ultrasound

A pelvic ultrasound uses soundwaves to create a picture of your uterus and ovaries. The soundwaves echo when they meet something dense, like an organ or tumour, then a computer creates a picture from these echoes. A technician called a sonographer does the scan. A pelvic ultrasound appointment usually takes 15–30 minutes.

A pelvic ultrasound can be done in two ways:

Abdominal ultrasound – To get good pictures of the uterus and ovaries, the bladder needs to be full, so you will be asked to drink water before the appointment. You will lie on an examination table while the sonographer moves a small handheld device called a transducer over your abdomen.

Transvaginal ultrasound –The sonographer inserts a small transducer wand into your vagina. It will be covered with a disposable plastic cover and gel to make it easier to insert. You may find a transvaginal ultrasound uncomfortable, but it should not be painful. If you feel embarrassed or concerned about having this procedure, you can ask for a female sonographer or have someone in the room with you (e.g. your partner, a friend or a relative) if that makes you feel more comfortable.

The transvaginal ultrasound is often the preferred type of ultrasound, as it provides a clearer picture of both the ovaries and uterus.

CT scan

A CT (computerised tomography) scan uses x-rays to create a detailed picture of the inside of the body.

A CT scan is used to:

• check your abdomen, chest and pelvic area
• look for signs that the cancer has spread outside the ovaries
• guide the needle when doing a biopsy.

The CT scanner is a large, doughnut-shaped machine. You will lie on a table that moves in and out of the scanner. CT scans are usually done at a hospital or radiology clinic.

You will be asked to not eat or drink (fast) before the scan. You may need to have an injection of a special dye. This dye is called contrast and it makes your organs appear white in the pictures so anything unusual can be seen more clearly.

While a CT scan can be noisy, it is painless. The contrast may make you feel hot all over and leave a bitter taste in your mouth, and you may feel a sudden urge to pass urine. These sensations usually pass quickly, but tell the person carrying out the scan if they don’t go away.

The scan takes about 10–20 minutes, but it may take extra time to prepare and then wait for the scan. You usually go home as soon as the CT scan is over.

Before having scans, tell the doctor if you have any allergies or have had a reaction to contrast during previous scans. You should also let them know if you have diabetes or kidney disease, or are pregnant or breastfeeding.

PET-CT scan

A PET (positron emission tomography) scan combined with a CT scan is a specialised imaging test. It provides more information about the activity of the cancer than a CT scan on its own, which mainly shows the shape and size of the tumours.

Only some people need a PET–CT scan. Medicare covers the cost of PET scans only for ovarian cancer that has returned, so they are not often used to look for ovarian cancer. If you are having chemotherapy before surgery, you may have this scan before the operation.

To prepare for a PET–CT scan, you will be asked not to eat or drink for a period of time (fast). Before the scan, you will be injected with a glucose solution containing a small amount of radioactive material. Cancer cells show up brighter on the scan because they take up more glucose than normal cells do.

You will be asked to sit quietly for 30–90 minutes as the glucose spreads through your body, then you will have the scan. The scan itself will take about 30 minutes. Let your doctor know if you are claustrophobic, as you need to be in a confined space for the scan. Any radiation will leave your body within a few hours.

MRI scan

An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to build up detailed pictures of the inside of your body. While not often used, an MRI may help if it is difficult to tell from the ultrasound whether an ovarian tumour is likely to be cancerous.

If you are having an MRI scan, let your medical team know if you have a pacemaker. The magnet can interfere with some pacemakers, but newer pacemakers are often MRI-compatible. As with a CT scan, a contrast dye might be injected into your veins before an MRI scan.

During the scan, you will lie on a bench inside a large metal tube that is open at both ends. The noisy, narrow machine makes some people feel anxious or claustrophobic. If you think you may become distressed, mention it beforehand to your medical team. You may be given a medicine to help you relax, and you will usually be offered headphones or earplugs. The MRI scan may take between 30 and 90 minutes.

Taking a biopsy

The only way to confirm the diagnosis of ovarian cancer is to remove a sample of tissue from the tumour (biopsy). This is sent to a specialist called a pathologist who checks it under a microscope for cancer cells.

In some cases, the diagnosis is confirmed after tissue is removed during surgery. If you cannot have surgery because the cancer has spread or because of some other medical condition, a biopsy may be taken in a different way.

Image-guided biopsy

A CT scan is used to guide where to put the needle. This is called an image-guided biopsy. You have a local anaesthetic injection in the skin over the area so that it goes numb. The procedure takes about 10 to 20 minutes. The cells in the sample will then be checked under a microscope to get more information about the cancer.

Removing a fluid sample

Sometimes fluid can build up in the abdomen. This is called ascites. If you have ascites, samples of the fluid can be removed and tested for cancer cells. The skin of the abdomen will be numbed and a needle will be inserted to collect some fluid. A CT scan may be used to guide the needle into place. The fluid is sent to a laboratory to check if it contains cancer cells.

Genetic testing after diagnosis

If you are diagnosed with epithelial ovarian cancer, your treatment team or a family cancer centre will discuss with you the option to have a blood test to look for a fault in the BRCA1, BRCA2 or another similar gene. This genetic test may be available through the public hospital system or with a Medicare rebate. The results will help work out if the ovarian cancer is sensitive to treatments such as targeted therapy.

If a cancer-related gene fault is found, Medicare rebates the cost of testing close adult female and male relatives to check their risk. (Men can inherit and pass on BRCA faults and may have a higher risk of prostate cancer.)

For more information, listen to our podcast episode on genetic tests, and order Ovarian Cancer Australia’s booklet on genetic testing.

→ READ MORE: Staging and prognosis for ovarian cancer

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