Trials aim to find out if a new treatment or procedure is safe, is better than the current treatment or helps you feel better.

If a clinical trial is suggested by the doctor, they will give the patient information to read about the trial and time to think about whether they wish to take part in the trial.

For a patient to enter a clinical trial, they must always give 'informed consent'. This means that the patient must have been told all about the trial, understood all of the information, and agreed to take part.

CCLG (Children's Cancer and Leukaemia Group) produce a booklet called A Guide to Clinical Trials, which describes the process of taking part in a clinical trial.

Clinical trials may not always be available, as the patient may not meet some of the requirements to be treated on a trial.

Find a clinical trial

Cancer Research UK can help you find out about current clinical trials, and provide excellent information about clinical trials including:

  • what clinical trials are
  • how to join a clinical trial
  • what you should know before taking part in a clinical trial

Search for clinical trials, and find out more information about becoming involved.

More detail about clinical trials

Clinical trials usually have three stages called phases:

  • Phase 1 or I: If a drug looks promising in laboratory studies, a phase 1 trial may be carried out. This is usually the first time a new drug is tried in people. These types of trials do not usually look at the effect on specific types of cancer but look at things such as side effects and the safest and most effective dose. These types of trials are usually done with a small number of people, usually 10-30.
  • Phase 2 or II: This type of trial may be open to people with specific types of cancer or a number of different cancers. They are usually carried out on more patients than phase I trials, usually around 100; mainly to look at, which type of cancer the drug works best against, to look at the best dose and side effects again, and to find out if the drug is worth taking to a much larger phase 3 trial.
  • Phase 3 or III: If a drug in a phase II trial looks as if it works as well or better than an existing treatment, a phase III trial is carried out. These trials are usually open to people with a specific type of cancer. Many more people are included in these trials, this helps to make sure doctors can see how well the drug may or may not help. The new drug or treatment is usually compared to an existing treatment. Patients will be put into one of at least two groups, for example, either the 'new drug group' or the 'existing treatment group.' This is done randomly by a computer, and prevents any human bias from putting certain patients into certain groups. This removes any possibility that the trial results could be cheated, for example by selecting healthier patients to take the new treatment.

You may see the terms 'blind' or 'double blind' randomised clinical trial. A blind trial means the patient does not know whether they are receiving the existing treatment or the new treatment. In a double blind trial neither the doctors nor the patients know which treatment they have received, until the end of the trial when the labels are decoded.

A single phase III trial can be carried out in several hospitals per country in many countries. This means that an even larger number of patients can be recruited and this provides more information about the new treatment.