A trial looking at radiotherapy and surgery for retroperitoneal sarcoma (STRASS)

Cancer type:

Soft tissue sarcoma




Phase 3

This trial compared radiotherapy before surgery to surgery alone for people with soft tissue sarcoma. 

This trial was for people with a soft tissue sarcoma behind the organs in their tummy (abdomen). Doctors call this a retroperitoneal sarcoma.

The trial was open for people to join between 2012 to 2017. The results were reported in 2019. 

More about this trial

Doctors usually treat sarcoma with surgery to remove it. In the retroperitoneum, the two most common tumour types are liposarcoma and leiomyosarcoma.

But sometimes the sarcoma can come back after treatment. So doctors are looking for ways to improve treatment.

In this trial, some people had surgery as usual. And some had radiotherapy before surgery. 

The aims of the trial were to find out:

  • if radiotherapy before surgery could delay the sarcoma coming back
  • more about the side effects    

Summary of results

The trial team found it was safe to have radiotherapy before surgery. But overall, adding radiotherapy didn’t improve treatment for everyone. Although the researchers say it might help some people with a type of sarcoma called a liposarcoma. 

About this trial
266 people joined this phase 3 trial. The trial took place worldwide.

People were put into 1 of 2 groups at random.

  • half had surgery
  • half had radiotherapy before surgery

The trial team found that it was safe to have radiotherapy before surgery. 

At 3 years, they looked at how well treatment worked. To do this, they looked at whose sarcoma hadn’t come back, at or near where it started. They found this was:

  • just under 6 out of 10 people (58.7%) who had surgery 
  • 6 out of 10 people (60%) who had radiotherapy and surgery

198 people had a type of sarcoma called a liposarcoma. At 3 years, the researchers looked at whose sarcoma hadn’t come back in this group. This was:

  • 6 out of 10 people (60%) who had surgery
  • just over 7 out of 10 people who had radiotherapy and surgery

Researchers say people with a slower growing liposarcoma might benefit from radiotherapy. But researchers need more time to follow these people to see how they do long term. 

Side effects
People who had radiotherapy had more problems with: 

  • low levels of lymphocytes in the blood
  • diarrhoea                 
  • feeling sick
  • tiredness                   

The trial team concluded that overall, radiotherapy before surgery wasn’t better than surgery alone for everyone with a retroperitoneal sarcoma. But they say radiotherapy may help people with slow growing liposarcoma. 

The next study planned will be for patients with aggressive high grade retroperitoneal sarcoma. It will look to see if chemotherapy before surgery will improve treatment.    

Where these results come from 

We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed) but may not have been published in a medical journal.  The figures we quote above were provided by the research team. We have not analysed the data ourselves.

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.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Mr Dirk Strauss

Supported by

European Organisation for Research and Treatment of Cancer (EORTC)
NIHR Clinical Research Network: Cancer

If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Wendy took part in a new trial studying the possible side effect of hearing loss

A picture of Wendy

"I was delighted to take part in a clinical trial as it has the potential to really help others in the future.”

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