What is a clinical trial?

Clinical cancer trials are cancer research studies that involve people. Their main purpose is to find a better way to prevent, diagnose or treat cancer, as part of a long, careful research process. Doctors and patients need evidence from clinical trials to know which treatments are the safest and most effective.

Researchers who run trials involving patients have to offer a treatment that is at least as good as, or possibly better than the best treatment that is currently available. All clinical trials are carried out following strict guidelines. Only patients who meet the eligibility criteria for a study can take part.

There are several different types of clinical trials:

Treatment trials

Treatment trials are the most common type of clinical trial. They are used to find out whether a different type of chemotherapy, radiotherapy or targeted therapy is more effective than what is already available. The aim of these studies can be to:

  • Test new treatments
  • Investigate new combinations of existing treatments or change the way current treatments are given to make them more effective, or to reduce side effects
  • Find out more about how cancer treatments work
  • Improve survival after treatment
  • Improve quality of life for people with cancer

The majority of cancer drugs and treatments that are currently used have been tested in clinical trials. Without this research it would not be possible to add to our knowledge of these treatments and improve outcomes for our patients.

There are four phases in clinical trials:

Phase I (1st in human)- These trials use a limited number of patients under close medical monitoring and aim to find best way to give treatment safely and determine dosage levels of the drugs.

Phase II- These also include a small number of patients under close medical monitoring and aim to find the effect of the drug on the specified cancer and any side effects.

Phase III- These trials include larger numbers of patients and aim to compare the drug’s effectiveness on specified cancers in comparison to current practices of care (first line) treatments using a randomisation method to remove bias. Its aim is to determine which group has better treatment outcomes and fewer side effects.

Phase IV- These trials are carried out after the drugs are approved for use outside of stages I - III. The aim is to find out more about the drug’s mechanism of action, toxicities and effects on patient’s quality of life.

Quality of life trials

Quality of life clinical trials look at improving patients’ well-being. Many quality of life studies are combined with treatment trials so doctors know the impact that certain treatments have on the everyday lives of patients.

This often includes questionnaires that people complete at different stages during the trial. The questionnaires can look at the psychological effects that the treatment has on patients and their family and carers.

Other examples of clinical trials include prevention trials, screening trials and diagnostic trials.

Participating in clinical trials

All patients who participate in clinical trials are volunteers, and can choose to stop their involvement at any time.

Before patients go on a trial, a doctor or research nurse will ask if they would like to be involved. Patients must then take part in a process called informed consent to make sure that they understand what the trial involves and what the trial is trying to find out.

The doctor and research nurse will provide a patient information sheet and give patients time to decide whether they would like to take part and ask any questions they may have.

If patients wish to participate in a clinical trial after learning all that is involved and what they would be expected to do, then they will need to sign and date the informed consent form.

The informed consent process does not end once patients sign the form. If new benefits, risks or side effects are found during a trial, the doctor must inform all of the participants in the trial.

If patients decide they do not want to take part in the trial, they can tell their doctor or research nurse. They can also withdraw from a trial at any time. Patients do not need to provide a reason for not taking part and there will be no change in the standard treatment they receive.

Above, clinical trials patient Bernadette Ross shares her experience of being part of research at The Clatterbridge Cancer Centre. Below is a video about research and clinical trials at Clatterbridge. To watch a British Sign Language version of this video, click here.