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

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Prostate cancer




Phase 1/2

This study is looking at using carbogen and nicotinamide (vitamin B3) with radiotherapy for prostate cancer.

Doctors often treat prostate cancer with radiotherapy. They know that radiotherapy is most successful when cancer cells have a high oxygen level. But cancer cells are often lacking in oxygen. The researchers think that increasing oxygen levels in prostate cancer cells may make radiotherapy more successful.

Carbogen is a gas that you breathe during radiotherapy. It is a mixture of 98 parts out of 100 (98%) oxygen and 2 parts out of 100 (2%) carbon dioxide. Nicotinamide is a vitamin tablet. Together they may increase oxygen levels in prostate cancer cells.

The aims of this study are to find out

  • If using carbogen and nicotinamide can improve radiotherapy for prostate cancer
  • What the side effects are

Who can enter

You may be able to enter this trial if you are attending the Mount Vernon Cancer Centre, Mount Vernon Hospital, Middlesex and you

You cannot enter this trial if you

  • Have prostate cancer that has spread to another part of your body, including lymph glands Open a glossary item in the area between your hip bones (pelvis Open a glossary item)
  • Have had a MRI scan in the past 3 months that showed your cancer had spread to nearby organs such as the back passage (rectum) or bladder (stage T4)
  • Have already had treatment for prostate cancer apart from anti androgen hormone therapy such as flutamide and bicalutamide
  • Have already had radiotherapy to the area between your hips (pelvic radiotherapy)
  • Are taking heart medicines called ACE inhibitors
  • Are not able to have a MRI scan - if you have certain types of metal surgical clips or plates in your body, or a pacemaker for example
  • Have another cancer apart from non melanoma skin cancer
  • Have another medical, psychological or social condition that could affect you taking part in this trial

Trial design

This is a phase 1/2 trial. There are 2 parts to this study. In the first part, the researchers want to find out how safe it is for men with prostate cancer having radiotherapy to have carbogen and nicotinamide. They will initially recruit 3 men. If their side effects aren’t too bad a month after finishing treatment, the researchers will recruit another 3 men. And so on, to a total of 12 men. If these men’s side effects aren’t too bad 3 months after finishing radiotherapy, the researchers will go on to the next part of the study. In this part the researchers will recruit another 38 men, making a total of 50 men in the study.

Everyone in the study will have carbogen and nicotinamide with radiotherapy. You have radiotherapy daily (Monday to Friday) for 7 ½ weeks.

You breathe the carbogen through a tight fitting face mask. You do this for 10 minutes before and 10 minutes during radiotherapy, so for about 15 to 20 minutes in total. To get use to the carbogen you can hold the face mask and control how much you breathe.

Nicotinamide is a tablet. You take it an hour and half before your radiotherapy.

As a part of your treatment you will also have hormone therapy (anti androgens) during and after radiotherapy. You have hormone therapy for 3 years. This is standard treatment for prostate cancer, which you would have whether or not you were in the study.

The researchers will ask 20 men to have an extra 6 MRI scans at different times during and after radiotherapy. Each scan takes about an hour. During the scans you breathe carbogen for about 10 to 15 minutes. This is to understand how much oxygen reaches prostate cancer cells and how it gets inside them.

You will be asked to fill in 2 questionnaires

  • Before starting radiotherapy
  • At 2, 4, 12 and 26 weeks after radiotherapy
  • Then every 6 months, for 5 years

These will ask how you have been and about any side effects you may have. This is called a quality of life study.

The researchers will ask your permission to take a small piece of the tissue (biopsy) taken when you were diagnosed. They want to see how oxygen levels affects the genes Open a glossary item in the tissue. This will be stored safely and used for future research.

They will also ask for a blood and urine sample. These will be sent to the Cancer Genetics Unit at the Royal Marsden Hospital. They will use these to help understand the genetics Open a glossary item of prostate cancer.

If you don’t wish to give these extra samples, you don’t have to. You can still take part in the main study.

Hospital visits

You see the doctor before taking part in this study and have some tests. These test include

During radiotherapy you see the doctor or nurse, to see how the treatment is going and if there are any side effects.

After radiotherapy you see the doctor at

  • 2 and 4 weeks
  • 3 and 6 months
  • 1 year
  • Then every 6 months for 5 years

Side effects

Carbogen gas can make you feel short of breath. This is usually mild, only lasts while you are breathing it in, and most people get used to it.

Nicotinamide can make you feel sick. Your doctor can give you medication to help. If necessary your doctor can reduce the dose.

The short term side effects of radiotherapy for prostate cancer include

The long term side effects of radiotherapy for prostate cancer include

  • A feeling of wanting to strain, and bleeding from the back passage (proctitis)
  • Difficulty passing urine
  • Leaking urine (incontinence)
  • Difficulty getting an erection (impotence)

We have more information on radiotherapy for prostate cancer in our prostate cancer section.

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)
National Institute for Health Research Cancer Research Network (NCRN)
Prostate Cancer UK

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 7670

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:

Rate this page:

No votes yet
Thank you!
We've recently made some changes to the site, tell us what you think

Share this page