What you should be told about a clinical trial
This page is about what you must be told before you agree to take part in a clinical trial. It contains information on
Before you take part
Legally and ethically, researchers must explain to you what a trial involves before you agree to take part.
They must tell you:
- what the trial is trying to find out
- what the different treatment groups are
- what the likely risks and side effects are
- what the benefits may be
- what tests or check ups you will have
- how often you will have follow up appointments and for how long
- whether the researchers would like to keep any blood samples, tissue samples or other samples to use for research in the future
They should also explain where you are likely to have treatment and whether you will need to stay in hospital or not.
The patient information leaflet
Full information about a trial should all be included in the patient information sheet (PIS) or patient information leaflet (PIL). A member of the research team will go through the information with you and give you a copy to take home and read in your own time. It will cover all the points listed above about what you should know.
You can refer back to the PIS when you are deciding whether to take part in the trial or not. You can also discuss it with your friends, family, GP, specialist or nurse. The research team should give you plenty of time to think about and ask any questions you have, before deciding to join the trial.
Giving your consent
Before entering the trial, you must sign a statement to say you have been told, and understand, what taking part in the trial means. This is called informed consent. 
You can't enter a trial without signing your agreement. You will have a chance to ask any questions you like if there is anything you don't understand. You may want to bring someone along with you to help make sure all your concerns are addressed. Please remember that you can say no to joining the trial if you don’t want to. It is entirely voluntary.
Informed consent is an ongoing process throughout the trial. So you should always be able to ask questions, and get answers to them, while you are in the trial.
Information about side effects
If the trial is looking at a very new treatment, the research team may not know much about the side effects yet. But you should be told everything they do know that is relevant.
If you want to leave a trial
Remember that you can withdraw from a trial at any time, without giving a reason. This will not affect your ongoing care or treatment in any way. You will go on to have the standard treatment for your type and stage of cancer.
References
Oxford Handbook of Clinical and Healthcare Research (1st edition)
R Sumantra, S Fitzpatrick, R Golubic and others
Oxford University Press, 2016
Related information
We have information about
New review due: 1 February 2025
Last reviewed
Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.
Search for clinical trials
Use our search page to find a trial by cancer type, drug name or trial name
