Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.
A trial of radiotherapy for cancer that has spread to another part of the body (SABR-COMET)
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This trial looked at stereotactic ablative radiotherapy (SABR) to treat cancer that has spread to another part of the body.
It was open for people to join between 2012 and 2016, and the team published the results in 2019.
More about this trial
When this trial was done, doctors often treated cancer that had spread with chemotherapy or radiotherapy, or a combination of the two. The aim of this treatment is to slow down the growth of the cancer rather than cure it.
Research has suggested that when there are only a few areas of cancer spread, treating these specific areas can help control the cancer for longer.
Stereotactic ablative radiotherapy (SABR) is a way of giving radiotherapy to an exact area of cancer very accurately.
Some people in this trial had standard treatment, and some had SABR. The researchers hoped that SABR may be better than the standard treatment for people whose cancer has spread.
The main aims of this trial were to find out:
- how well SABR works for cancer that has spread
- more about the side effects
- how it affects people’s quality of life
Summary of results
The results showed that stereotactic ablative radiotherapy (SABR) helped stop cancer growing and meant people lived longer. But it also caused more side effects.
Everyone taking part in this trial had cancer that had spread to up to 5 other areas of the body. These areas included the lungs, bone and liver.
The people who joined the trial were put into 1 of 2 treatment groups at random. There were twice as many people in the SABR group as there were in the standard treatment group. This is called 2:1 randomisation.
A total of 99 people joined this trial and were put into 1 of 2 treatment groups. There were:
- 33 people in the standard treatment group
- 66 people in the SABR group
- 1 area in 42 people
- 2 areas in 32 people
- 3 areas in 18 people
- 4 areas in 4 people
- 5 areas in 3 people
The research team looked at how long it was before people’s cancer started to grow again. They found it was longer for people who had SABR:
- 6 months for those who had standard treatment
- 12 months for those who had SABR
They then looked at how long people lived for, and found this was also longer for people who had SABR:
- 28 months for those who had standard treatment
- 41 months for those who had SABR
When they looked at how many people had died, they found this was lower in the SABR group:
- 16 out of 33 people (48%) who’d had standard treatment
- 24 out of 66 people (36%) who’d had SABR
The research team looked at the change in size of 157 specific areas of cancer, to see if they’d grown after treatment or not. The number of areas of cancer that had not grown was:
- 28 out of 57 (49%) in the standard treatment group
- 75 out of 100 (75%) in the SABR group
Quality of life
The research team measured changes in people’s quality of life using several different questionnaires. The people taking part completed these questionnaires before, during and after treatment.
The research team found there wasn’t any difference in the results between those who had standard treatment and those who had SABR.
People in both groups had some side effects. But more people who had SABR had moderate or severe side effects:
- 3 people (9%) who had standard treatment
- 19 people (29%) who had SABR
Doctors think 3 people who had SABR died because of the treatment, rather than because their cancer had grown. Two had lung infections and one died following an operation to help with a stomach ulcer caused by the radiotherapy.
No one in the standard treatment group died because of the treatment they had.
The research team concluded that SABR did help stop the cancer growing and meant that people lived longer. But it also caused more side effects.
They recommend that more trials are done to find out more about how well SABR works for specific cancer types. And that it might to useful to find out if there is a maximum number of areas of cancer spread where SABR is helpful.
Where this information comes from
We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (
How to join a clinical trial
Dr Stephen Harrow
Experimental Cancer Medicine Centre (ECMC)
London Regional Cancer Programme (LRCP)
NIHR Clinical Research Network: Cancer
NHS Greater Glasgow and Clyde
Ontario Institute for Cancer Research (OICR)