Cancer research trials may be carried out to:

• test new treatments, such as new chemotherapy drugs, gene therapy or cancer vaccines
• look at new combinations of existing treatments, or change the way they are given, in order to make them more effective or to reduce side effects
• compare the effectiveness of drugs used for symptom control
• see which treatments are the most cost-effective
• discover which treatments give the fewer side effects
• find out how cancer treatments work
• see which treatments are most convenient for patients

Trials are the only reliable way to find out if a different operation, or type of chemotherapy or radiotherapy, is better than what is already available. If experts already knew that the new treatment was better than the standard treatment, there would be no need for a clinical trial and you would be offered it routinely as part of your care.

If you decide to take part in a trial you will not automatically get the new treatment being tested. You will, however, be helping to improve the general understanding of cancer and the best way to treat it.

You should only agree to take part in a trial if you are completely happy with what you are being asked to do. It's important to know that if you do take part in a trial you can decide to leave it at any time, without giving a reason. However, if you're having a new treatment as part of the trial, you may not be able to continue having the new treatment if you leave. In this situation you would be given the standard treatment.

By learning more about clinical trials now – with time to think about all the issues – we hope that you will feel more confident in your decision, whether or not you agree to take part.

The UK government and health departments have recognised the benefits of clinical trials for patients. The National Cancer Research Institute is a partnership of health departments, the Medical Research Council and major cancer charities.

In England, the National Cancer Research Network provides support for doctors and nurses carrying out clinical trials in hospitals, hospices and the community. In Wales there is the Wales Cancer Trials Network, in Scotland the Scottish Cancer Research Network, and in Northern Ireland there is the Northern Ireland Cancer Clinical Trials Network.