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Clinical trials

Clinical trials explained

Clinical trials are research studies, used to show whether a new approach to prevention, screening, diagnosis, or treatment works better than what is currently used and is safe. People volunteer in clinical trials to help test how well the new way (intervention) works and if it causes side effects or other problems.

If the new way is shown to work better than the existing approach, it may become the new standard of care for people with cancer in future. Some clinical trials compare existing approaches to see which one is more effective.

Visit the Victorian Cancer Trials Link

Understand clinical trials in your language

Learn about the role and value of clinical trials through a series of multilingual videos produced by the  Australian Clinical Trials Alliance.

The videos are available in Arabic, Chinese ( simplified and traditional), Filipino, Greek, Hindi, Italian, Punjabi, Spanish and Vietnamese. Written versions of the videos are also available.

More resources in other languages

Cancer research overview

Cancer research has led to the medical treatments and health programs available today. These advances have improved outcomes for people with all types of cancer, with increases in both length of survival and quality of life. The search for better ways to prevent, diagnose and treat cancer is ongoing. 

There are three main types of cancer research:

  • population research – researchers known as epidemiologists look for patterns and trends to work out how and why cancers occur in groups of people (populations).
  • laboratory research – scientists do experiments with the building blocks of disease, such as cells and blood, to try to understand how cancer works, and they also study and develop new drugs and treatments in the laboratory.
  • clinical research – research is done on people to better diagnose, prevent and treat cancer, often in a hospital or treatment centre. Population research and laboratory research are often the starting point for clinical research, which may involve clinical trials.

Key questions

Why get involved in research?

When people take part in cancer research, whether they are affected by cancer or not, it helps researchers learn more about cancer and the ways to prevent, diagnose and treat it.  

Many people diagnosed with cancer who join a clinical trial or another research study do so because they want to help improve outcomes for others in the future, as well as for themselves. Adults and children can take part in research in different ways, including:  

  • consenting to their medical records and personal information being accessed
  • doing surveys and interviews
  • being involved in a clinical trial
  • agreeing to be examined regularly by health professionals
  • allowing samples of cells or tissue taken during tests or treatment to be used for research outside of their own medical care.

Who can participate in research?

All research studies, including clinical trials, have guidelines setting out who can take part. These are known as eligibility criteria. Most cancer research involves current patients, but some studies focus on carers, family members, people at risk of cancer or people who have not been affected by cancer. Anyone under the age of 18 needs permission from a parent or guardian before joining a research study.

To make sure results reflect Australia’s diverse population, it is important that research involves people of all ages, genders and sexualities, as well as people from a wide range of social, economic, racial and cultural backgrounds.

Where does research take place?

Cancer research is carried out in many places, including hospitals, treatment centres, laboratories and universities. Sometimes you can be involved in cancer research from home. For example, you might have treatment or medicines mailed to you, or you might be asked to fill in a survey or complete a telephone or face-to-face interview.  In Australia, some people are now taking part in clinical trials that use telehealth (teletrials ).

What are the benefits of joining a clinical trial or other types of research?

There are many advantages to being involved in a clinical trial or other research study. Depending on the type of research, the benefits may include:

  • knowing you have made a valuable contribution to helping others in the future
  • joining programs or having medicines or other treatments that are not readily available outside of the study and may be better than the current standard treatment for that disease
  • getting access to expensive drugs that your specialists recommend but that are not currently supported by the Pharmaceutical Benefits Scheme (PBS)
  • seeing your treatment team, including specialists, more often
  • taking an active role in your health care
  • learning new ways to improve your lifestyle
  • improving or maintaining your quality of life
  • feeling that you have tried all treatment possibilities.

Taking part in research doesn’t always mean you will be better off than before or compared to other people in a similar situation. Some people may not respond in the way researchers hope and will not benefit from being involved in the research.

Your doctor and the clinical trials or research nurse will discuss the possible advantages and disadvantages for you before you join a research study.

Is research safe?

Understandably, people want to know if there are any risks to taking part in research. Researchers must follow strict guidelines to make sure clinical trials and other research studies are as safe as possible for everyone involved. This is called their duty of care.

Before any research involving people can begin, it must be approved by a special group known as a human research ethics committee. As part of this process, researchers identify risks that might occur, such as possible side effects.

Before you agree to take part in research, you must be told about these risks, how you will be monitored for problems, and what will be done to help you if problems occur. To reduce potential risks, clinical trials are arranged in a series of steps known as phases.

How long do research studies last?

From start to finish, clinical trials and other research studies may take several months or many years, but you may only need to be involved for some of this time.  If you are consideri ng joining a clinical trial or research study, you will be given information (called participant information ) that will  set out what you need to do and how long you will be involved.

Studies have what is known as a recruitment phase. This involves finding people to join the study. It usually occurs over a few months or years until the required number of people have agreed to take part. The study is then closed to new participants.  

Studies ma y also have what is known as a follow-up phase. People may be followed up at set intervals for months or years after they have received the treatment or approach being tested in the research study . This allows researchers to understand the long-term effects of treatments, monitor the general health of participants, and collect data about long-term survival and quality of life.  

Can I still have other treatments?

Ask your doctor whether being involved in the research will affect any other treatments you’re having or planning to have. These may include:

Your doctor may suggest stopping or delaying some treatments, or adjusting them in some way (e.g. by changing the dose).

It is important to let the research team know about any other medicines, supplements or complementary therapies you are having, as these may interact with the treatment being tested and cause harmful side effects.

Is it free to join a research study?

Joining a clinical trial or other research study is free for Australian citizens and residents, and you should not be asked to pay to join. The cost of trial-related treatment, tests and check-ups will be paid for by the organisation that is funding or conducting the research, sometimes called the sponsor.

You will usually still have to pay for any treatments or tests you would normally pay for as part of your standard care. The participant information will outline any extra costs to you.

Will I be paid?

People participating in cancer research usually don’t get paid. This is because offering people money to join a clinical trial may put too much pressure on them to agree.

In some circumstances, you may be paid back for certain expenses (e.g. for travel, parking, light refreshments). These are known as out-of-pocket costs. The participant information will outline what expenses will be covered.

Can I be involved in more than one research study?

You may be interested in joining multiple clinical trials and other research studies. Check with the research team whether you can be part of more than one study at the same time. If you can, think about whether you’ll be able to commit to all the requirements of the studies. With clinical trials for medicines, you can usually only join one trial at a time.

Who works on clinical trials and other research studies?  

A  team of people work on research studies , and some of their roles may overlap. If you decide to join a clinical trial or other research study , you may have contact with all or some of these people:  

  • Investigator – also known as a researcher, an investigator develops and plans research studies, and obtains, analyses and publishes the results.
  • Nurse or research assistant – coordinates finding people for the trial (recruitment) by talking to potential participants, making sure they are eligible and explaining the purpose of the trial, and acts as a link between the patient and the researchers or the health care team.
  • Study coordinator – ensures the trial meets ethical and legal requirements, and applies for grants and manages budgets.
  • Cancer specialist – may be a medical oncologist, surgeon, radiation oncologist or haematologist. A cancer specialist supervises your treatment, follow-up and overall care.
  • Other professionals  including a pharmacist, allied health practitioners and complementary therapists.

In most cases, your cancer specialist will continue to look after your overall cancer care while you are on a clinical trial or other research study .


Teletrials for cancer

In Australia, some people are now taking part in clinical trials that use telehealth (teletrials). This means that the research team use telephone or video calls to talk with patients and with local health professionals who are delivering part of the trial.

Tele-trials were developed to make joining a clinical trial easier for people in rural and remote locations, but they can make it more convenient for anyone to take part. You can talk to your cancer specialist about whether there is a tele-trial you could join. If you are already involved in a clinical trial, you could ask if parts of it can be delivered by telehealth.

Learn about our clinical trials advocacy

The clinical trials process

Cancer clinical trials are clinical research studies that use volunteers to test new ways (interventions) to diagnose, treat and manage cancer.

A medicine or another intervention can be developed in a laboratory and tested on animals, but it is only once it has been tested on the human body that we can know it works in people. It also has to be tested on enough people to show that any benefit is not just a random effect for a single person.

Types of trials

Cl inical trials are designed to answer different research questions:

  • Treatment trials – test new treatments, new ways of giving existing treatments, or new combinations of treatments. They look at whether the treatment works and if it causes side effects. Most cancer clinical trials in Australia are treatment trials.
  • Prevention trials – work out whether medicines and health programs lower the risk of developing diseases such as cancer.
  • Screening trials – look at new approaches of detecting diseases before symptoms appear.
  • Diagnostic trials – identify more accurate or easier tests for diagnosing a particular disease in people who have signs or symptoms.
  • Quality of life trials – test ways to improve the comfort and quality of life of people who have cancer. They are done alongside a treatment trial. 

Phases of a clinical trial

Researchers spend many years developing new treatments or medicines in the laboratory before  they are used in clinical trials involving people. They then plan the clinical trial to progress in a series of steps called phases. Every phase considers whether the risks outweigh the benefits.

Information gathered in each phase determines whether the study can move on to the next phase, and whether the medicine or treatment is approved for use. There can be up to four phases, but not all clinical trials go through every phase.

  • Phase 1: Safety – tests the safety of a new treatment by finding the safest dose and the best way it can be given, identifies side effects and checks how the treatment works with other medicines or food (interactions). This phase is the first study in people and often includes people with different types of cancer.
  • Phase 2: Effectiveness – builds on the results of the phase 1 trial by continuing to test the safety of the new treatment. This phase begins to assess how well the new treatment works on the disease.
  • Phase 3: Comparison – tests if the new treatment is better than the best currently available treatment (standard treatment) by comparing side effects, survival and quality of life. This phase collects information that allows new treatments and existing treatments to be used in new ways or for different diseases.
  • Phase 4: Follow-up – identifies how well the new treatment works when used more widely in the real world by monitoring the long-term benefits and risks. This phase looks for other uses of the treatment.


Randomised controlled trials

It is important for researchers to know that the results of a study are accurate and not caused by chance. This means they must follow strict guidelines. Researchers also need to make sure their own or the participants’ ideas or beliefs about the research don’t unfairly influence the results (bias).

There are various ways to make sure clinical trials are fair and reliable. Many clinical trials are randomised controlled trials (RCTs), which helps prevent bias, so it is the best way to test if a new treatment works.

What is a randomised controlled trial?

RCTs mean participants in the study are put into two or more groups (known as treatment arms) at random. The two groups then receive different treatments, and the results of the different groups are compared. Researchers cannot choose who goes into each group. Most phase 3 trials and some phase 2 trials are randomised. 

  • Test or experimental arm – this group is given the new treatment that is being tested. Sometimes, the experimental treatment is given in addition to the current standard treatment.
  • Control arm – this group receives the current standard treatment for the disease or, if a current standard treatment is not available, an inactive treatment known as a placebo.

When randomly allocated groups are compared with each other, it is possible to work out which treatment is better. This is because researchers can be certain that the results are related to the treatment, and not to any other factors.

A non-randomised trial means everyone receives the same experimental treatment. This method may be used for phase 1 and phase 2 trials, or where the cancer being treated is rare and it is hard to conduct a randomised trial.

Standard treatment and placebos

In a randomised controlled trial, people in the control arm may receive the standard treatment or a placebo. Standard treatment is the current most effective treatment given to people for their disease or condition. 

Placebo is an inactive or 'dummy' treatment. It is made to look, taste or feel like the treatment being tested, but it doesn’t have any active (therapeutic) ingredients (if a medicine) or beneficial effect. Examples of placebos are sugar pills and saline injections.

A placebo is used to show whether any improvements are because of the actual treatment or because of other factors linked with being in the study, such as being more closely monitored or simply expecting the treatment to be helpful. If the people on the experimental treatment improve more than those on the placebo, this provides stronger evidence that it is the experimental treatment that is responsible.

Participants will be told if a study uses a placebo, but they won’t be told which treatment they are having, and the research team usually don’t know either.  Placebos may be used together with standard treatm ent or on their own, but only when there is not existing standard treatment available.

Other types of clinical research

Clinical trials are not the only type of clinical research studies. You may also be invited to get involved in:

  • Behavioural research – looks at why people act the way they do and what can be done to improve their ability to cope with cancer.
  • Psychosocial research – a type of behavioural research that looks at how cancer affects people emotionally, psychologically and socially.
  • Translational research – aims to get new treatments and prevention strategies into practice quickly by sharing information back and forth between researchers and hospitals, treatment centres or health professionals.
  • Registry trial – collects information from people with a particular type of cancer who are having routine treatment. It can’t be used for testing new treatments, but it can answer a range of questions about existing treatments.

Understanding Clinical Trials and Research

Download our Understanding Clinical Trials and Research booklet to learn more

Download now  


Expert content reviewers:

A/Prof Brett Hughes, Senior Staff Specialist, Medical Oncology, Royal Brisbane and Women’s Hospital and The Prince Charles Hospital, and Associate Professor, The University of Queensland, QLD; Christie Allan, Clinical Trials Lead, Cancer Council Victoria, VIC; Dawn Bedwell, 13 11 20 Consultant, Cancer Council Queensland, QLD; Joanne Benhamu, Senior Research Nurse, Team Lead, Lung, Colorectal and Palliative Care Trials, Parkville Cancer Clinical Trials Unit, Peter MacCallum Cancer Centre, VIC; Louise Dillon, Consumer; Sabina Jelinek, Clinical Nurse Research, St John of God Murdoch Hospital, WA; Chloe Jennett, Program Coordinator, Cancer Research, Cancer Council NSW; Carmel McCarthy, Consumer; Alison Richards, Research Unit Manager, Medical Oncology Clinical Trials Unit, Flinders Medical Centre, SA; Prof Jane Ussher, Translational Health Research Institute (THRI), School of Medicine, Western Sydney University, NSW; Prof Janette Vardy, Medical Oncologist, Concord Cancer Centre, and Professor of Cancer Medicine, The University of Sydney, NSW.

Page last updated:

The information on this webpage was adapted from Understanding Clinical Trials and Research - A guide for people with cancer, their families and friends (2022 edition). This webpage was last updated in March 2022.

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