A trial to learn more about weekly radiotherapy for invasive bladder cancer and to look at a different way of planning treatment (HYBRID)

The trial team found that adaptive radiotherapy could be a good treatment option for people with bladder cancer who aren’t able to have surgery or several weeks of daily radiotherapy.

Trial design
The people who took part in this trial had bladder cancer that had grown into the muscle wall of the bladder. But it hadn’t spread to any other part of the body. They weren’t well enough to have an operation to remove their bladder or to have radiotherapy every day for several weeks. They had radiotherapy once a week for 6 weeks.

Some people taking part had treatment to the same area each week. This is standard radiotherapy.

Some people had treatment to a slightly different area each week, depending on the results from their scan on that day. This is adaptive radiotherapy. They had treatment to either the standard area (‘medium’ size) or to an area smaller or larger than the standard. 

The trial team wanted to see what side effects people had, and how well adaptive radiotherapy worked. 

They also wanted to see how many people in the adaptive group had treatment to a smaller or larger area. In other words, how many people had non standard radiotherapy. 

Results
A total of 65 people took part in this trial. The average age of people taking part was over 80. They all had other medical conditions which meant they would find usual treatment too difficult.

The people taking part were put into a treatment group at random. There were:

• 32 people in the standard radiotherapy group
• 33 people in the adaptive radiotherapy group

HYBRID randomisation diagram

Side effects
The trial team were able to assess side effects of 63 people who took part. 

A few people had moderate side effects that affected areas around their bladder, such as their bowel:

• 4 out of 30 people (13%) who had standard radiotherapy
• 2 out of 33 people (6%) who had adaptive radiotherapy

And a few people taking part had moderate side effects that affected their bladder:

• 5 out of 30 people (17%) who had standard radiotherapy
• 3 out of 33 people (9%) who had adaptive radiotherapy

HYBRID bar chart

Size of radiotherapy treatment area
Everyone who had radiotherapy in the standard treatment group had treatment to the same (medium) size area each time. It didn’t change according to scan results.

There were 33 people in the adaptive radiotherapy group. Some had treatment to a medium area. But 28 people had at least 1 of their 6 treatments changed to either a smaller area or larger area because of the scan result on the day of treatment:

• 2 people had radiotherapy to a small area on each day of treatment
• 22 people had radiotherapy to 2 different size areas on different days (small and medium, for example)
• 4 people had radiotherapy to all 3 size areas on different days (small, medium and large) 

The 33 people who had adaptive radiotherapy had a total of 193 doses (called fractions) of radiotherapy between them:

• 46 doses were to a small area
• 117 doses were to a medium area
• 30 doses were to a large area

HYBRID bar chart 1 diagram

So nearly 4 out of 10 fractions (39%) were not standard medium size. This is more than the team were expecting.

How well treatment worked
The research team were able to look at how well the treatment worked in 48 people who took part. 

At 3 months after treatment, they found that the cancer hadn’t grown in 39 people (81%). When they looked at the 2 groups separately, they found it was:

• 17 out of 23 people (74%) who had standard radiotherapy
• 22 out of 25 people (88%) who had adaptive radiotherapy

HYBRID bar chart 2 diagram

They also found that more than 6 out of 10 people (62%) were living a year after treatment. And nearly 5 out of 10 people (46%) were living 2 years after treatment.

This is lower than it would be for people who are able to have intensive treatment aimed at curing their cancer. But higher than it would be for people who either have treatment aimed at controlling symptoms or don’t have any treatment.

Relieving symptoms
The research team asked the people taking part about the symptoms of bladder cancer they were having, and whether they had got better or worse. 

They found that more people who had adaptive radiotherapy said their symptoms had improved, compared to those who had standard radiotherapy. But the difference wasn’t big enough for the research team to say for sure that it was because of the different treatments. It could have been due to chance.

Symptoms got better for between less than 2 out of 10 people (16%) and nearly 9 out of 10 people (89%), depending on the symptom:

Conclusion
The research team concluded that it was possible to give adaptive radiotherapy once a week to people unable to have surgery or more frequent radiotherapy. And that it was a useful treatment for people with bladder cancer that had spread into the bladder wall but not anywhere else in the body.

They suggest adaptive radiotherapy should be considered as a treatment for this group of patients. 

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 (peer reviewed ) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.