Does ultrasound screening for ovarian cancer help?

Photo of a woman at a doctor's appointment (PantherMedia / Wavebreakmedia Premium)

Women are often offered ultrasound scans to screen for ovarian cancer. But research has shown that this type of screening doesn’t have any benefits. It also leads to false alarms and unnecessary surgery.

Ovarian cancer can develop slowly over time without causing any symptoms. Because of this, it is often only discovered at an advanced stage. The risk of ovarian cancer increases with age.

This is shown in the following table: It describes how many out of 1,000 women of a certain age will develop ovarian cancer, and how many will die of this disease, within 10 years:

Age

Number of women who will develop ovarian cancer within the next 10 years

Number of women who will die of ovarian cancer within the next 10 years

35 years old

1 out of 1,000

Fewer than 1 out of 1,000

45 years old

2 out of 1,000

1 out of 1,000

55 years old

3 out of 1,000

1 out of 1,000

65 years old

4 out of 1,000

3 out of 1,000

75 years old

4 out of 1,000

4 out of 1,000

Overall, about 14 out of 1,000 women develop ovarian cancer at some point in their lives. About 10 out of 1,000 women die of it.

Abnormal tissue can sometimes be felt by a doctor during a pelvic exam using their hands. Many doctor’s practices also ask women whether they would like to have an ultrasound scan to screen for ovarian cancer.

In Germany, statutory health insurers will only pay for this screening examination if the doctor thinks there might be a problem with the ovaries – for instance, if the woman has certain symptoms. When ultrasounds of the ovaries are done for screening purposes, women have to pay for them themselves. In Germany, these kinds of diagnostic examinations are known as "individual health care services," or IGeL for short. The ultrasound exam costs between 9 and 53 euros.

Does ultrasound screening for ovarian cancer improve the chances of survival?

No. Two good studies – involving a total of almost 300,000 people – looked into whether ultrasound screening reduces the risk of dying of ovarian cancer. They found that women who had regular ultrasound screening were just as likely to die of ovarian cancer as those who didn’t have regular ultrasound screening for this disease.

There are various possible explanations for this. For instance, aggressive forms of ovarian cancer sometimes can’t be detected in ultrasound images until they have spread to other parts of the body (metastasis). Or they grow so fast that they develop and spread within a few months, between one screening examination and the next.

What are the disadvantages of ultrasound screening for ovarian cancer?

In the studies, more women in the “screening groups” had their ovaries removed unnecessarily. This is because the ultrasound scans led to the discovery of changes in the ovaries, and surgery was then carried out to take a closer look. Sometimes doctors can only find out for sure whether it’s ovarian cancer by removing the whole ovary. The ovary tissue is then examined in a laboratory to see if there are any tumor cells in it.

Of all the women who had surgery following the discovery of something unusual during ultrasound screening, only about 10% actually had ovarian cancer. So 90% of them had their ovaries removed although they didn’t need to.

Because most “suspicious” things seen on the ultrasound turn out to be harmless, ultrasound screening for ovarian cancer often leads to unnecessary worries and psychological stress.

Ultrasound screening in figures

The largest study on the pros and cons of ultrasound screening for ovarian cancer was carried out in Great Britain over a time period of ten years. The results of this study are shown in the following table:

Over the course of 10 years...

Women who participated in the screening program

Women who did not participate in the screening program

... this many women were diagnosed with ovarian cancer:

6 out of 1,000

6 out of 1,000

… this many women died of ovarian cancer:

3 out of 1,000

3 out of 1,000

… this many women had an ovary (or both ovaries) removed:

47 out of 1,000

14 out of 1,000

In other words:

  • Ultrasound screening did not improve the chances of survival.
  • As a result of the screening examination, 33 out of 1,000 women had their ovaries removed unnecessarily.

What does the ultrasound examination involve?

If you have an ultrasound examination of your ovaries, you will be asked to undress from the waist down and sit on a gynecological chair or lie down on an examination table. In order to be able to get good images of your ovaries, the doctor will gently insert a long, thin ultrasound transducer into your vagina (transvaginal ultrasound). The doctor will move the transducer around a little. This allows him or her to look at other organs too (the womb, fallopian tubes and bladder). The ultrasound images of the organs can be seen on a screen. Although the examination isn’t painful, some women find it unpleasant. The doctor can often already determine a few things during the examination, such as whether it’s a non-cancerous (benign) cyst or possibly cancer.

If the doctor sees anything unusual, she or he may recommend doing other examinations such as a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan. These examinations are mainly used to see whether a tumor has already spread. If the results suggest that it might be cancer, the affected ovary is removed in an operation and then examined to see if there are any cancer cells in it.

What are the side effects of having ovaries removed?

Like any operation, the surgical removal of ovaries can lead to complications such as infections, wound healing problems, thrombosis and anesthetic-related problems. Between 4 and 15 out of 100 women had such complications in the studies.

If only one ovary is removed, women of childbearing age can still get pregnant afterwards. If a woman has both ovaries removed, she can no longer become pregnant. The ovaries produce hormones, so removing both ovaries results in a sudden drop in hormones. This immediately leads to the menopause, which is usually associated with things like hot flashes and sweats. For these reasons, doctors remove only one ovary whenever possible – particularly if the woman would like to have (more) children.