A trial looking at radiotherapy with or without carbogen and nicotinamide (ARCON) for cancer of the voice box (larynx)

Cancer type:

Head and neck cancers
Laryngeal cancer




Phase 3

This trial was trying to find out if nicotinamide and carbogen could improve radiotherapy for cancer of the voice box (cancer of the larynx or laryngeal cancer).

Doctors often use radiotherapy to treat cancer of the larynx. Radiotherapy works very well for small tumours in only one part of the larynx, but not so well for larger tumours.

Doctors think that radiotherapy is most successful for cells that have a higher oxygen level. But cancer cells are often lacking in oxygen. If the researchers could increase the oxygen level in laryngeal cancer cells, this may make the radiotherapy kill more cancer cells.

In this trial the researchers were looking at nicotinamide and carbogen as a way of increasing the oxygen levels in laryngeal cancer cells. Nicotinamide is a form of vitamin B that you take as a tablet. 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.

The aim of the trial was to see if nicotinamide and carbogen treatments could improve radiotherapy for laryngeal tumours that were stage T2, T3 or T4.

Summary of results

The researchers found that ARCON could reduce the number of laryngeal cancers that came back in the head and neck area, but did not help people to live longer.

The trial recruited 345 people.

  • 174 had radiotherapy
  • 171 had radiotherapy plus carbogen and nicotinamide (ARCON)

The people having ARCON had a slightly lower dose of radiotherapy.

If the cancer had not come back in the larynx after 5 years, the researchers call this local control. If it had not come back in lymph nodes in the area, they call it regional control.

They found that local control after 5 years was about the same in both groups. But regional control after 5 years was

  • 86 out 100 people (86%) in the radiotherapy group
  • 93 out of 100 people (93%) in the ARCON group

Side effects were about the same in both groups and having ARCON did not affect the number of people living with or without any signs of cancer after 5 years (overall survival).

We have based this summary on information from the team who ran the trial. As far as we are aware, the information they sent us has not been reviewed independently (peer reviewed Open a glossary item) or published in a medical journal yet. The figures we quote above were provided by the trial 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

Professor M Saunders

Supported by

Dutch Cancer Society

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

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 296

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

Around 1 in 5 people take part in clinical trials

3 phases of trials

Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.

Last reviewed:

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