In focus: approaches to earlier diagnosis - introduction to screening

[OvacomeSupport]

Hello

In last month’s ‘Health in Focus’ posts for Ovarian Cancer Awareness Month, we looked at some of the ways of raising awareness of the symptoms of ovarian cancer (healthunlocked.com/ovacome/..., healthunlocked.com/ovacome/..., healthunlocked.com/ovacome/... and healthunlocked.com/ovacome/.... By raising awareness, we aim to help the public and health professionals to recognise these symptoms and enable earlier diagnosis.

This month we’ll be looking at other ways to promote earlier diagnosis. Today we’ll provide a general introduction into some of the issues around screening and in our later posts we’ll look at research into ovarian cancer screening, some of the approaches to screening and earlier diagnosis and the existing screening programmes for breast, cervical and bowel cancer.

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.

Screening programmes take place on a large scale and involve many thousands of patients. Before introducing a screening programme that will affect so many people, it’s therefore important to have strong evidence that it will save lives. This includes answering questions about how early and how accurately the screening can detect the changes it’s looking for.

To answer these questions, research looks into the possible ways of screening people and comparing participants who are screened with those who don’t have screening. This involves observing large numbers of people over a long period to draw firm conclusions about the effects of the screening and whether it saves lives.

The accuracy of a medical test, including screening, is measured in two ways, which are called sensitivity and specificity. Sensitivity means successfully identifying those who have the change the test is looking for. Specificity means correctly identifying those who do not have the change.

These measures can have important consequences for people taking part in a screening programme, as they influence how many will receive correct and incorrect test results.

If a test has 80% sensitivity, 80 out of 100 people with the change will be correctly told that they have it and 20 will be incorrectly told that they don’t have it. These incorrect results are called false negatives.

If it has 60% specificity, 60 out of 100 people without the change will be correctly told that they don’t have it, whereas the other 40 will be incorrectly told that they do. These 40 incorrect results are called false positives.

You can read more about sensitivity and specificity at academic.oup.com/bjaed/arti...

False negative results are likely to reassure people that they don’t have cancer when they do. They may not seek further advice about their symptoms, or their doctors may look for alternative causes. This could lead to delays in diagnosis.

False positive results are likely to cause distress and anxiety to those people who are incorrectly told that they may have cancer and could also mean that someone has surgery that they did not need. There can also be complications of surgery and long-term effects, especially if the person has existing health conditions or is frail.

Ovarian cancer is most often diagnosed at stages 3 and 4, when it has spread beyond the pelvis (The stages of ovarian cancer | Ovacome). It is then more difficult to treat compared to stage 1, when it is confined to the ovaries. Because treatment at stage 1 is more likely to be successful, a screening programme that can detect ovarian cancer before it spreads has the potential to make a significant difference.

So far, the trials of ovarian cancer screening haven’t confirmed that a screening programme would save lives. There is research ongoing, and we’ll look at it in more detail in next week’s post. You can also find out more in our information booklet on ovarian cancer screening 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