Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.
A trial looking at radiotherapy and a new treatment for bladder cancer (Bladder Arcon - BCON)
This trial looked at radiotherapy with or without carbogen and nicotinamide tablets for bladder cancer that had spread into the muscle (locally advanced). It was supported by Cancer Research UK.
The trial was open for people to join between 2000 and 2006, and the team first published results in 2010. They published further results in 2021.
More about this trial
Doctors can use both surgery and radiotherapy to treat locally advanced bladder cancer. Having radiotherapy means that people don’t have their bladder removed. But the cancer can sometimes come back and they may need more treatment.
Radiotherapy is more likely to kill cancer cells if the cells have plenty of oxygen. The aim of the treatment in this trial was to increase the amount of oxygen available to cancer cells. The researchers hoped that this would help to stop the cancer from coming back.
People in this trial took nicotinamide tablets and used a breathing apparatus called the carbogen breathing system, for a few minutes before and during each radiotherapy treatment.
The main aims of this trial were to find out:
- how well having carbogen and nicotinamide with radiotherapy worked
- more about the side effects
Summary of results
The trial team found that there was a significant benefit in adding carbogen and nicotinamide to radiotherapy treatment for people with locally advanced bladder cancer.
A total of 333 people joined this trial, and 327 went on to have treatment:
- 163 had radiotherapy only
- 164 had radiotherapy with carbogen and nicotinamide
When the researchers compared the average time people lived, they found it was:
- about 2.5 years (30 months) for those who had radiotherapy only
- about 4.5 years (54 months) for those who had radiotherapy with carbogen and nicotinamide
The most common side effects of radiotherapy with carbogen and nicotinamide were:
- feeling or being sick
- feeling that you need to pass urine more often than normal
When the researchers compared the long term side effects of both treatments they found they were about the same.
The research team concluded that adding carbogen and nicotinamide to radiotherapy did help people with locally advanced bladder cancer. And the side effects were similar to having just radiotherapy.
Different doses of radiotherapy
In 2020 researchers combined the results for people who took part in two trials – this trial (BCON) and another trial for bladder cancer called BC2001. They published these results in 2021.
Radiotherapy is measured in Gray (Gy). You often have several doses called
The research team combined the results from the 2 trials, to see how well people did.
They looked at the results for 326 people who took part in BCON, and 456 people who took part in BC2001. So a total of 782 people:
- 376 who had 64Gy in 32 fractions
- 406 who had 55Gy in 20 fractions
The results showed that, 5 years after treatment, the cancer had come back in fewer people who had 55Gy in 20 fractions. How long people lived for and the side effects they had were very similar in the two groups.
The research team concluded that 55Gy in 20 fractions is as good as 64Gy in 32 fractions, for bladder cancer that has grown into the bladder muscle wall. They suggest that 55Gy in 20 fractions should be the standard treatment for this group of patients.
Where this information came from
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 (
How to join a clinical trial
Professor Peter Hoskin
Cancer Research UK
NIHR Clinical Research Network: Cancer
This is Cancer Research UK trial number CRUK/01/003.