Did the test change how people were diagnosed?

Key points

• Some people are diagnosed with cancer after a usual NHS screening test, whereas other people are diagnosed different ways, like after visiting their GP or A&E.
• More cancers were diagnosed through screening in people who had the blood test. 
• Fewer cancers were diagnosed in an emergency situation in people who had the test.

One of the aims of the NHS-Galleri trial was to look at how people who got cancer were diagnosed.

In the NHS, people can be diagnosed with cancer in different ways. The way people are diagnosed can affect their healthcare experience and outcomes.

Some people are diagnosed with cancer after a usual NHS screening test, like a mammogram, before they have symptoms. There are four NHS screening programmes in England, for breast, bowel and cervical cancer, and for people at high risk of lung cancer.

Other people are diagnosed with cancer in different ways, like after going to their GP or A&E, because they have visited a doctor with painful or uncomfortable symptoms.

Cancers found through screening are usually diagnosed as part of routine NHS processes. Cancers diagnosed in emergency situations are often found when someone becomes unwell and needs urgent care.

People who are diagnosed after a screening test often do better than people diagnosed in other ways. People diagnosed in an emergency situation tend to have worse outcomes. This might be because they are more likely to have more advanced cancer.

What the researchers looked at

The researchers measured the number of cancers found in people who had the blood test (test group) and the number of cancers found in people who did not have the test (control group).

They then looked at how the people who had cancer were diagnosed. 

The researchers compared these routes between people who had the test and those who did not. 

What the results show

In the group who had the blood test, more cancers were diagnosed through screening and fewer cancers were diagnosed in emergency situations.

Around four times more cancers were detected by screening when the blood test was used alongside usual screening than through screening programmes alone. 

A total of 25% fewer people in the test group were diagnosed in an emergency situation, such in A&E, compared with the control group. 

What the results mean

These results help to understand how cancers might be diagnosed if the test is used alongside existing NHS screening programmes.

Cancers can be diagnosed in different ways, including after screening or when someone visits a doctor.

Understanding these patterns might help inform how different approaches to cancer detection could be used across the population.