A study looking at radiotherapy with carbogen and nicotinamide for prostate cancer (PROCON)

Cancer type:

Prostate cancer




Phase 1/2

This study looked at using carbogen and nicotinamide during radiotherapy for prostate cancer.

The study was open for people to join between 2011 and 2013. The team presented the results at a conference in 2020.

More about this trial

Doctors often use radiotherapy to treat prostate cancer. We already knew from research that radiotherapy can work better when cancer cells have a high oxygen level. But cancer cells often have a low oxygen level. 

The research team hoped that increasing oxygen levels in prostate cancer cells may make radiotherapy work better.

Carbogen is high dose oxygen that you breathe during radiotherapy. It is a mixture of:

  • 98 parts out of 100 (98%) oxygen
  • 2 parts out of 100 (2%) carbon dioxide

Nicotinamide is a vitamin B3 tablet. 

The main aims of this study were to find out:

  • if carbogen and nicotinamide can help radiotherapy work better
  • more about the side effects

Summary of results

Trial design
This trial was for men with prostate cancer that had grown through the prostate, but not spread to another part of the body. Everyone taking part in this trial had the same treatment.

They all had:

  • radiotherapy every day (Monday to Friday) for about 6 or 7 weeks
  • carbogen gas via a face mask during each radiotherapy treatment
  • a nicotinamide tablet about an hour and a half before each radiotherapy treatment

A total of 50 people joined this trial. They were all due to have radiotherapy for prostate cancer.

The research team looked at how many people’s cancer had not come back, 5 years after treatment. They found it was nearly 9 out of 10 people (87%).

They also looked at how many people were living, 5 years after treatment. They found it was more than 9 out of 10 people (92%).

This is about the same as, or a little higher than, what you would expect if people had radiotherapy without carbogen and nicotinamide.

Carbogen and nicotinamide did cause some side effects. But they were all mild or didn’t last long. No one had any serious side effects. The most common side effect was feeling sick.

The research team concluded that giving carbogen and nicotinamide during radiotherapy was safe and may be helpful. They suggest larger trials are done to look at this treatment for prostate cancer in more detail.

More detailed information
There is more information about this research in the reference below. 

Please note, this article is not in plain English. It has been written for health care professionals and researchers.

Prostate radiotherapy with carbogen and nicotinamide. Final results of the phase 1b/II PROCON trial
K Yip and others
Radiotherapy and Oncology, 2020. Issue 152, S369–70.

Where this information comes from    
We have based this summary on the information in the article above. This has been reviewed by independent specialists (peer reviewed Open a glossary item) and published in a medical journal. We have not analysed the data ourselves. As far as we are aware, the link we list above is active and the article is free and available to view.

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

Dr Roberto Alonzi

Supported by

East and North Hertfordshire NHS Trust
Experimental Cancer Medicine Centre (ECMC)
NIHR Clinical Research Network: Cancer
Prostate Cancer UK

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.

Keith took part in a trial looking into hormone therapy

A picture of Keith

"Health wise I am feeling great. I am a big supporter of trials - it allows new treatments and drugs to be brought in.”

Last reviewed:

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