Informed consent


Informed consent is an ethical and legal requirement for any human research. It is central to the respect of participants in clinical trials, and their freedom and ability to choose if and how they would like to participate.

Informed consent can only be obtained when participants have enough information to make a decision, and to understand the proposed research and the implications that their participation may have on their lives. Consent must be voluntary, with no coercion to participate. The specific requirements for obtaining informed consent depends on the trial, and the laws, codes, ethics and cultural sensitivities of the community the research is occurring in.

The consent process aims to develop a mutual understanding between participants and the researchers. So individual participants need to be given the opportunity to ask questions as often as they need to. They also need to be able to discuss the information and decisions with others, such as their family, friends or their regular doctor.

Informed consent process

Informed consent is an ongoing process throughout the trial that requires communication between researchers and participants. This is particularly important in medical research, because sometimes researchers may learn new information during a trial that could change something. For example, researchers may learn about evidence of better outcomes with an existing or new treatment, or evidence of harm from the treatment under investigation. Participants must be informed of changes like these and be able to consider whether they are happy to continue with the trial.

To make an informed and voluntary choice, participants need to understand the purpose, methods, demands, risks and potential benefits of the research they are considering participating in. This information needs to be conveyed to participants in a way that is suitable for them.

In clinical trials, information to guide consent is provided in different ways. The main way is through patient information sheets, which explain the details of the trial in plain language for the participant to read and keep to refer to throughout the trial. Information is also provided verbally by clinicians or researchers throughout the trial. Providing information more than once, in different ways or by different people, can help participants understand and remember information.

Expressing and documenting consent

Consent must be documented. Australia’s guidelines require only that it be explicitly expressed in some form. For cancer clinical trials, consent is almost always obtained in written form, where participants sign a written document that details what they are consenting to.

Challenges in gaining consent

Participants often find it hard to understand medical research and treatment options. Clinicians can find it hard to present treatment options clearly. 

A potential participant’s physical and emotional wellbeing can affect how well they understand medical information. Patient misunderstandings and misconceptions can make clinical trial discussions even harder. 

Clinicians may have concerns about discussing complex medical concepts with patients. They need to balance expert advice without coercing patients to participate in clinical trials.

A pathway for communication and decision making

There are 4 key concepts to ideal patient communication and decision making:

  • establishing the patient and clinicians or researchers as a team working together
  • helping patient understanding and the expectation of full disclosure about trials, treatments and their risks and benefits
  • avoiding coercion of patients to participate
  • following a consultation pathway.

Establishing the team

To establish a team, the clinician needs to understand how much information the patient wants to know and how involved they want to be in decision making. It can be helpful to find out what a patient already knows about their condition and their overall health literacy. 

To establish the team relationship, clinicians should explicitly invite questions and comments from patients. They can also portray the patient as an active participant in the discussion and decision-making process. Clearly outlining all the treatment options is also helpful to show that clinicians and patients need to work together to come to a decision appropriate for that person. 

Helping patient understanding

Clinicians can use different strategies and tools to help patients understand information about the trial, such as:

  • non-verbal cues, including body language and eye contact
  • language that the clinicians use when communicating with patients, including using open questions, simple language and analogies can help patient understanding
  • physical aids, including diagrams, question prompt lists or trial information sheets
  • validation, which involves acknowledging the patient’s situation, their emotions and feelings as being normal and that they can ask questions. This may also include taking as much time as the patient needs with the clinician and outside the consultation.

Avoiding coercion

Coercion means pressuring someone to do something. The terms that clinicians use can affect coercion. For example, the term ‘eligible’ for a trial may make a patient think that they are lucky or has won something by being eligible. The term ‘suitable’ may be more appropriate.

Making sure the patient is involved in the treatment decision-making can help to ensure their preferences are considered. Giving people sufficient time to discuss treatment options and to decide on treatment can help to avoid coercion. Some patients may prefer that their clinician make the decision for them, and this is ok as well.

Following a consultation pathway

The consultation pathway ensures that clinician and the patient have a shared understanding of the process so far. Clear communication and understanding at this stage are needed to support the rest of the trial.

The next step is pathway 1 – discussing the standard treatment options. These should be discussed in enough detail for the patient to have a very clear idea of those options before the concept of a clinical trial in introduced. 

The next step is pathway 2 – introducing the idea of a clinical trial. It is important to acknowledge that you are about to add a whole level of complexity to the discussion and to gain the participant’s agreement to move to this conversation.