A trial to see if dietary supplements can affect abnormal cervical cells (CRISP-1)

Cancer type:

Cervical cancer




Phase 3

This trial tried to find out if a dietary supplement could help abnormal cervical cells return to normal. This trial was supported by Cancer Research UK.

A cervical smear test can pick up different stages of ‘abnormal cells’ on the neck of the womb (the cervix). As these cells are ‘pre cancerous’, the treatment you have can prevent cervical cancer. What you have depends on whether the cells show borderline, mild, moderate or severe changes (dyskaryosis).

If you have moderate or severe cell changes, you will then have a colposcopy. This is a close examination of your cervix. If you have borderline changes, you will probably have another smear test 6 months later, or you may have a colposcopy. If you have mild changes you will either have another smear test 6 months later or a colposcopy.

A supplement called diindolylmethane (pronounced di-in-doll-ile-me-th-aine), called DIM for short, is found in vegetables such as broccoli, cabbage and cauliflower. Research has shown that DIM may change pre cancerous cells back to normal cells.

In this trial, women who had borderline or mild cervical cell changes took a form of DIM, called BioResponse DIM, every day for 6 months. The aim of this trial was to see if DIM helped abnormal cells return to normal.

Summary of results

The trial team found that taking diindolylmethane (DIM) for a short while was not likely to help abnormal cells of the cervix return to normal.

This was a randomised trial where neither the patient, nor their doctor, knew what they were taking (double blind). Of the 600 women who took part in this trial

  • 400 had DIM
  • 200 had the dummy drug (placebo Open a glossary item)

After 6 months these women had a follow up colposcopy and cervical smear test

  • 373 had DIM
  • 178 had dummy drug
  • 49 did not attend their follow up colposcopy

Of the 373 women who had DIM their colposcopy and cervical smear test

  • 185 were normal
  • 87 had borderline changes
  • 72 had mild changes
  • 19 had moderate changes
  • 7 had severe changes
  • 1 not enough cells were taken
  • 2 results were missing

Of the 178 who had the dummy drug

  • 98 were normal
  • 40 had borderline changes
  • 26 had mild changes
  • 6 had moderate changes
  • 6 had severe changes
  • 1 result was missing

As twice as many women took DIM, there was no difference statistically between the 2 groups. The trial team concluded that having DIM for 6 months was not likely to help abnormal cells of the cervix return to normal.

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 (peer reviewed Open a glossary item) and published in a medical journal. 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 Peter Sasieni
Professor Alison Fiander

Supported by

Cancer Research UK
Cardiff University (School of Medicine)
Cervical Screening Wales (CSW)
NIHR Clinical Research Network: Cancer
Queen Mary University of London

Other information

This is Cancer Research UK trial number CRUK/04/027.

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 507

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

Wendy took part in a new trial studying the possible side effect of hearing loss

A picture of Wendy

"I was delighted to take part in a clinical trial as it has the potential to really help others in the future.”

Last reviewed:

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