A trial of higher dose radiotherapy to treat pain caused by mesothelioma (SYSTEMS-2)
Cancer type:
Status:
Phase:
This trial compared the usual dose of radiotherapy with a higher dose to treat pain caused by mesothelioma.
It was for people whose mesothelioma started in the 2 sheets of tissue known as pleural membranes (or pleura). The pleura covers the lungs. When a cancer starts here it is called a pleural mesothelioma.
The trial was open for people to join between 2016 and 2022. The team presented the results in 2024.
More about this trial
People with mesothelioma often have pain. Unfortunately, regular painkillers don’t always work, so some people have radiotherapy to help with the pain.
Radiotherapy can be useful in treating pain caused by mesothelioma. But we don’t know the best dose and schedule to use.
The usual dose of radiotherapy once a day for 5 days helps control pain in just under half of the people with mesothelioma. Researchers hoped that increasing the dose would provide better pain control in more people.
Half the people in the trial had the usual dose of radiotherapy over 1 week. The other half had the increased dose of radiotherapy over 2 weeks.
The aims of the trial were to:
- find out if a higher dose of radiotherapy works better than the usual dose to treat pain
- learn more about the side effects
- find out whether the people having the higher dose of radiotherapy lived longer
Summary of results
The initial results of this trial showed both radiotherapy schedules are tolerated. People having either schedule had few side effects, and they were not severe.
Results
This was a 
. In this , a computer put 110 people into 1 of 2 groups. The 2 groups were:
- 56 people were to have the usual radiotherapy dose over 1 week
- 54 people were to have the increased dose of radiotherapy over 2 weeks
The number of people who completed their radiotherapy was:
- 48 in the usual radiotherapy
- 51 in the increased dose of radiotherapy
The team looked at how many people in each group had a meaningful improvement in pain 5 weeks after radiotherapy. They found that it was:
- 20 people (36%) who had the usual radiotherapy dose
- 23 people (43%) who had the increased dose of radiotherapy
These numbers look a bit different. But there is not a big enough difference to say for sure that it was due to the different doses. It could have been due to chance.
The team also looked at how long it was until half the people in each group had died. This is called overall median survival. They found it was:
- 4.8 months for people who had the usual dose
- 6.6 months for people who had the increased dose
They also looked at how many people were alive at 6 months and 1 year after treatment. At 6 months it was:
- 4 out of every 10 people (40%) who had the usual dose
- 5 out of every 10 people (50%) who had the increased dose
At 1 year it was:
- 9 out of 100 people (9.5%) who had the usual dose
- 31 out of 100 people (31%) who had the increased dose
Side effects
In general, the side effects were mild.
During treatment those who had the increased dose reported slightly more:
- feeling and being sick
- pain during the treatment period
After treatment more of these people had skin changes in the radiotherapy field.
All these side effects were a little bit more severe than those who had the usual dose.
During the follow up period more of the people who had the usual dose experienced pain.
We have general information about the side effects of radiotherapy for pleural mesothelioma.
Conclusion
The trial team concluded that these initial results show both doses are well tolerated.
There is a suggestion that more people who had the increased dose lived for at least 12 months after treatment.
Where this information comes from
We have based this summary on the information in the article below. This has been reviewed by independent specialists () and published in a medical journal. We have not analysed the data ourselves. It is not in plain English. It has been written for healthcare professionals and researchers.
2880: SYSTEMS-2: randomised phase II study of radiotherapy dose escalation in pleural mesothelioma
M J Ashton and others
Radiotherapy and Oncology, 2024. Volume 194, Supplement 1, pages S1787 to S1789.
Recruitment start:
Recruitment end:
How to join a clinical trial
Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.
Chief Investigator
Professor Anthony Chalmers
Supported by
Cancer Research UK Clinical Trials Unit, Glasgow
Beatson Cancer Charity
June Hancock Mesothelioma Research Fund
NHS Greater Glasgow and Clyde
University of Glasgow
The London Community Foundation
If you have questions about the trial please contact our cancer information nurses
Freephone 0808 800 4040
