Should I join a cancer clinical trial?

If you are thinking about taking part in a clinical trial it is important to understand what is involved and what it might mean for you.

It is always your decision if you wish to join a clinical trial or not. If you join and then change your mind, you can leave at any time. Your healthcare team will support you whatever you decide.

Every trial is led by a main researcher, who is often a medical doctor. The research team running the trial also includes:

  • doctors
  • nurses
  • research co-ordinators
  • other healthcare professionals.

If you are eligible to join a trial, a member of the team will give you information about:

  • what the trial is trying to find out
  • what the trial involves
  • what you will have to do
  • possible benefits and risks of taking part
  • other treatments that may be right for you.

They will give you an information leaflet about the trial. You can take this away and read it in your own time. You may want to talk to your family or friends. You should feel comfortable that you have all the information you need and feel able to ask any questions.

Before you decide to join a trial, you should think carefully about what taking part may mean. This includes possible benefits and possible harms of being involved.

If you decide to join, the research team will ask you to sign a form saying you agree (consent) to take part. You cannot be entered into a trial without giving your consent.

If you decide not to take part in a trial, your cancer doctors and nurses will respect your decision. You do not have to give a reason and it will not affect your future care. Your cancer doctor will give you the standard treatment and care for the type and stage of cancer you have.

Benefits of taking part in a trial

Clinical trials are designed to benefit the people who take part. Whatever treatment you have, there are safety measures to keep any risks to you as low as possible.

Joining a trial sometimes means you can have a new treatment that is not otherwise available. The new treatment may work better than the standard treatment, although this is not certain. By standard treatment, we mean the most effective treatment available now.

You will be carefully monitored by the research team. They may want you to have regular tests during or after treatment. This may include:

The research team may also ask you extra questions about how you are feeling. This means they can see any changes in your health and deal with them as soon as possible.

Cancer clinical trials gather information that may improve cancer care in the future. Some people say they feel they are helping other people living with cancer by taking part in a clinical trial.

Risks or disadvantages of taking part in a trial

Trials are set up to try to be as safe as possible. But there is a risk that you could get unpleasant or unexpected side effects or that the treatment could harm you.

It is also possible that the treatment will have no more benefit for you than the standard treatment. It may even be less effective than the standard treatment.

Depending on the type of trial, you may be put in the control group. This means you will receive standard treatment. You will not have the new or trial treatment.

There may be practical issues that make taking part in a trial more difficult. Before you join a trial, it is important to understand what these are. For example, some trials may involve:

  • more appointments or time in hospital
  • longer travel times, if the trial is only available at a certain hospital
  • extra blood tests or scans
  • additional costs such as travel, car park charges or time off work
  • completing regular forms, questionnaires or diaries.

During cancer treatment trials

During a trial that tests cancer treatments, the research team are responsible for your treatment and care. Your cancer team are still involved and support you. But you may go to a different clinic for appointments. You may see a doctor or nurse from the research team more often. Your research team can explain what to expect.

Your research team may also talk to people involved in other parts of your healthcare if needed. For example, they will tell your GP about the treatment you are having. Your GP is responsible for your day-to-day health at home, so it can help them to know.

Your information and confidentiality

Your medical records are confidential. They are mainly used by your healthcare team and the research team as part of your care. When you are part of a clinical trial, they can also be looked at by:

  • the staff who are co-ordinating the trial
  • people from the company or group involved in the trial
  • people from organisations that monitor the safety of trials.

This is to check the trial is collecting the right information accurately.

These people are not allowed to give information about you to anyone outside the healthcare and research team looking after you.

When the clinical trial results are published, you will not be named.

If you want to leave the trial

Even if you agree to take part in a trial, you can leave at any time. You do not need to give a reason. Before you make the decision, it is a good idea to talk it over with your:

  • cancer doctor
  • specialist nurse
  • research nurse.

They can make sure you have all the information and support you need.

If you have been having a new treatment as part of a trial, you may not be able to continue with it. Your cancer doctor will give you the standard treatment for the type of cancer you have. By standard treatment, we mean the most effective treatment available now.

After the trial

When your part in the clinical trial is complete, the research team will become less involved in your care. Your cancer doctor and healthcare team will manage your ongoing care again.

You may still have follow-up appointments or tests as part of the trial. Some clinical trials collect information about how long people live after treatment. To do this, researchers may monitor people for 5 years, 10 years, or even longer.

Trial results

Often the research team will tell you how and when the trial results are likely to be ready. They may ask if you want to be contacted in the future with more information as results become available.

The results of most clinical trials are published in medical journals. It may take many years for this to happen. To get enough information, some trials need hundreds and sometimes thousands of people to take part over a number of years.

Sometimes results are reported in newspapers or discussed on TV or radio. This is usually after the results have been presented at a medical conference or published in medical journals.

Are cancer clinical trials safe?

Clinical trials are carefully planned to make sure they are safe. There are several ways that people are protected before and during a trial.

  • Ethics committee

    The plan for the trial is called the trial protocol. Before a trial can start, this has to be approved by a research ethics committee. These are independent groups made up of:

    • research or healthcare professionals
    • other people with an interest in research ethics.

    They make sure your rights and well-being are a priority. They also check if the likely benefits of the trial are greater than the possible risks.

  • Trial management

    An independent group, or groups, oversee the trial to make sure it continues to be as safe as possible for the people taking part. They check how the trial is being run and that the trial plan (protocol) is being followed. They also monitor the information being collected to check the safety of the trial and how well treatment is working. They can stop a trial if it is causing harm to a person. For example, they could stop a trial if people are having severe side effects.

    They will also stop a trial early if the results show the new treatment is much better than standard treatment. This means doctors can start using the new treatment instead of the standard treatment.

  • Medicines and Healthcare products Regulatory Agency

    The Medicines and Healthcare products Regulatory Agency (MHRA) is a government body. It makes sure trials meet standards of good practice to protect the people taking part. The MHRA must give approval for all cancer treatment trials before they can start. It continues to monitor trials for as long as they last.

    It can also make changes to the trial plan (protocol) and interrupt or end the trial in some circumstances. Researchers must report all serious side effects from a trial treatment to the MHRA. They then review this.

  • Insurance

    It is rare for a drug or treatment to seriously harm anyone in a trial. But all clinical trials must have insurance to protect the people taking part. There are different arrangements for this, depending on who is running or overseeing the trial.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Prof Tim Iveson, Consultant Medical Oncologist.

    With thanks to: Kelly Leonard, Senior Research Nurse & Team Lead; Sara Herrero Santaolalla, Specialist Clinical Pharmacist; Dr Mangesh Thorat, Researcher, Trialist and Cancer Prevention Expert.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 August 2022
Next review: 01 August 2026
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.