In focus: approaches to earlier diagnosis - ovarian cancer screening with diagnostic tests

[OvacomeSupport]

Hello

This month in our ‘Health in Focus’ posts, we’re looking at ways to promote earlier diagnosis of ovarian cancer. Last week, we posted an overview of some aspects of screening (healthunlocked.com/ovacome/... Today we’ll look at research into ovarian cancer screening using the same techniques that are currently used to diagnose it. In our next two posts we’ll explore some of the research into other approaches to diagnosing ovarian cancer earlier and look at the existing screening programmes for other types of cancer.

As we mentioned last week, screening means testing for early signs of a health change, before symptoms develop. Diagnostic testing, by contrast, is done in response to symptoms and aims to find out what is causing them.

Research studies have been done into using the tests that are currently used to diagnose ovarian cancer as a screening method. This means doing CA 125 blood tests and/or ultrasound scans in people without symptoms to find out whether they might have ovarian cancer that hasn’t started to cause symptoms yet.

One issue with this is that CA125 is only raised in around 50 per cent (50 in 100) of women with early stage ovarian cancer. Additionally, a high level of CA125 can also be due to a number of other reasons, such as pregnancy, having a period, fibroids and endometriosis. It is not specific to ovarian cancer.

Ultrasound results can be abnormal even when there is no cancer.

Although internal examinations to look for enlarged ovaries are sometimes part of the diagnostic process, they haven’t been found to be an effective way of diagnosing early-stage ovarian cancer and so aren’t suitable for screening.

As we mentioned in last week’s post, so far the evidence from the studies that have been done hasn’t confirmed conclusively that ovarian cancer screening with diagnostic tests saves lives, although further research results are awaited. Here is an overview of the research to date.

The PLCO study, which was carried out in the USA between 1993 and 2001, didn’t find conclusive evidence that annual CA 125 tests and ultrasound scans saved lives in the general population. It also found that false positive results (patients incorrectly diagnosed with ovarian cancer who didn’t have it) resulted in harm for a significant number of participants. For example, among those who underwent unnecessary surgery, about 20 major complications occurred for every 100 operations. Its results therefore didn’t support the introduction of this method of ovarian cancer screening in the general population.

The UK Familial Ovarian Cancer Screening Study (UKFOCSS) (ascopubs.org/doi/full/10.12... study looked at screening in people whose risk of ovarian cancer is 10% or higher because of their family history or inherited gene changes. CA 125 tests were done four-monthly and used to calculate their risk of ovarian cancer. Ultrasound scans were done once a year if the result of the risk calculation process was normal. If a result was abnormal, an ultrasound scan was done in response.

For this group of people already at increased risk of ovarian cancer, screening made a significant difference to the stage at diagnosis compared with those diagnosed who had not been screened. Those who had screening were more likely to be diagnosed before their cancer became advanced and to have their cancer completely removed by surgery, which is associated with better outcomes.

However, people who are known or suspected to have a gene alteration which increases their risk of ovarian cancer may also be able to have surgery to remove their ovaries and/or fallopian tubes (ovarian.org.uk/ovarian-canc..., ovarian.org.uk/ovarian-canc.... This is a more effective way of reducing their risk of developing ovarian cancer than screening. Therefore, a screening programme hasn’t been introduced for this group of people. If you carry a genetic change that increases your risk of ovarian cancer, or if you’re concerned about your risk because of your family history, you can talk to your hospital team or GP about your options.

A large UK study into screening of the general population hasn’t yet reported its final results and conclusions. It’s called the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) (ctu.mrc.ac.uk/studies/all-s... and, similarly to UKFOCSS, is looking into screening using CA 125 testing and ultrasound scanning. One group of people received CA 125 testing and, again, if their risk was calculated to be abnormal they also underwent ultrasound scanning. Another group had annual ultrasound scans and, if a scan was abnormal, a second scan was done. A control group did not have any screening.

The results that have been released so far suggest that the CA 125 screening with additional ultrasound scans has significantly increased the number of early-stage ovarian cancers diagnosed compared with those receiving ultrasound scanning only or no screening.

There were also some false positive results, causing anxiety to those wrongly diagnosed and a small number of unnecessary surgeries. The rate of complications seen in those surgeries was lower than in the PLCO study, at 3.1 per 100 for those in the CA 125 screening group and 3.5 per 100 for the ultrasound screening group. However, longer-term follow-up was needed to confirm whether implementing a screening programme would be predicted to save lives. The final results are expected to be released later this year.

You can read more about screening for ovarian cancer in our information booklet at Ovarian cancer screening | Ovacome.

If you would like more information about screening for ovarian cancer, please get in touch with our Support Service on 0800 008 7054 or at [e-mail].

Best wishes

Julia

Ovacome Support