A trial looking at a second treatment of radiotherapy for cancer that has spread to the bone (SC20 trial)

Cancer type:

Cancer spread to the bone

Secondary cancers

Status:

Results

Phase:

Phase 3

This trial looked at the possibility of using a second radiotherapy session for pain caused by cancer that had spread to the bone. This trial was supported by Cancer Research UK.

Cancer can spread to the bone and it can be painful. Doctors can treat painful cancer spread to the bones with radiotherapy, which often works very well.

But sometimes it doesn’t work. Or it only works for a short time and then the pain comes back again. If this happens, some doctors give a second radiotherapy session, and some don’t. No one was sure how well a second radiotherapy session worked. Or what was the best dose to give.

In this trial, people who had already had radiotherapy to their bones once, but were still having pain, had more radiotherapy. They either had a low dose of radiotherapy in a single session (fraction Open a glossary item ) or a higher dose in 5 sessions.

The aims of the trial were to find out how well a second radiotherapy session worked for pain caused by cancer spread to the bones. And which dose of radiotherapy was best.

Summary of results

The trial team found that a lower dose in a single session of radiotherapy was as good as a higher dose in 5 sessions as a second treatment for bone pain caused by cancer.

This was a phase 3 trial. It recruited 850 people. It was a randomised trial. The people taking part were put into 1 of 2 groups

Half of the people in the trial had a single session of radiotherapy
Half of the people in the trial had 5 sessions of radiotherapy

The researchers looked at how people were 2 months after their treatment. They found that the bone pain had responded in

28 out of every 100 people (28%) who had the single radiotherapy session
32 out of every 100 people (32%) who had the 5 radiotherapy sessions

The trial team then did a 2nd analysis. They took out those people who

Didn’t have radiotherapy as instructed in the protocol of the trial
Unfortunately died before the team could follow them up to assess their bone pain

This left them with the number of people in each group who were treated and followed up according to the protocol of the trial. There were

285 people who had a single radiotherapy session
263 people who had 5 radiotherapy sessions

Out of these people, the researchers found that bone pain had responded in

45 out of every 100 people (45%) who had the single radiotherapy session
51 out of every 100 people (51%) had 5 radiotherapy sessions

This could have happened by chance, so it wasn't statistically significant Open a glossary item .

Two weeks after radiotherapy the most common side effects reported were loss of appetite and diarrhoea.

The trial team concluded that a low dose of radiotherapy in a single session was no worse than a higher dose in 5 sessions as a second treatment for bone pain caused by cancer.

We have based this summary on information from the team who ran the trial. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.