Women with possible ovarian cancer symptoms often have a blood test and ultrasound. But for women without symptoms, these aren't helpful.
Ovarian cancer is a malignant tumour in one or both ovaries. It usually occurs in women over the age of 50 who have gone through menopause, but can also occur in younger women.
If a woman has symptoms that might be ovarian cancer, doctors will often order a blood test (“CA-125”) and a pelvic ultrasound.
But for women who don’t have symptoms, these tests are not helpful in looking for ovarian cancer. Here’s why:
The test results are not always accurate
Women with a high CA-125 level don’t always have ovarian cancer. Instead, they may have another cancer or a different condition such as cirrhosis, pelvic inflammatory disease, fibroids, or endometriosis.
And half of women with early cancer have a normal CA-125 level.
Also, ultrasounds are not good at finding early ovarian cancer. They often show cysts that are benign (not cancer). This can lead to unnecessary surgery.
Studies using CA-125 and ultrasound testing to screen women for ovarian cancer have found these tests do not help prevent deaths from ovarian cancer.
The tests can lead to risky procedures
If a CA-125 test or ultrasound shows something that isn’t normal, doctors will often do surgery to check the ovary for cancer. The ovary is usually removed. One major study showed that 15 women out of 100 had complications from surgery.
Even with a laparoscopy or “keyhole” surgery, there’s a risk of injury. The surgery is done through a tiny cut with very small tools.
Some women choose to have both ovaries removed during the procedure. This can cause early menopause, which can increase the risk of hip fractures, heart attacks, and possibly dementia.
When are the tests worth the risks?
The CA-125 test and an ultrasound may be helpful if you have symptoms of ovarian cancer.
Also, if your doctor feels something abnormal on a physical exam, these tests may help diagnose the problem.
You should talk to your doctor about being tested if you have a high risk of ovarian cancer, including:
A family history of ovarian, breast, uterine, or colon cancer.
Or, inherited risks, such as the BRCA1 or BRCA2 gene mutation or Lynch syndrome. These are major risks of ovarian cancer.
If you have ovarian cancer, the CA-125 test can be helpful. Your doctor can use the test to check if treatment is helping, or if the cancer has come back.
What are the symptoms of ovarian cancer?
Most women have very few symptoms but you may experience one or more of the following:
lower abdominal pain or pelvic pain
pain during sex
pain related to your bowels
a feeling that you want to pass urine urgently and more frequently
a change in appetite or feeling full quickly
a distended (swollen) abdomen.
It's OK to ask questions
If you have questions about your symptoms or the medicines managing your symptoms, speak with your health professional.
You can also download this information as a pdf (447 KB).
Developed by Choosing Wisely New Zealand, 2018. Adapted from Choosing Wisely USA/Consumer Reports (2014) “Screening tests for ovarian cancer – when you need them and when you don’t” and the Royal College of Obstetricians and Gynaecologists (2016) “Information for you – Ovarian Cancer”. Choosing Wisely does not assume any responsibility or liability arising from any error or omission or from the use of any information in these resources.
This article is part of our content on Choosing Wisely, a campaign encouraging a change in thinking by health professionals and consumers to avoid unnecessary medical intervention.