Clinical trials

Clinical trials are an essential step from laboratory research to real improvements in health care. They are part of the final stages of the long research process. Trials show whether new approaches to prevention, screening, diagnosis and treatment work better than those currently used, and whether they are safe.

There are several types of clinical trials designed to answer different research questions.

  • Prevention trials – evaluate whether medicines or health programs lower the risk of developing diseases such as cancer.
  • Screening trials – look at new methods of detecting diseases before symptoms appear.
  • Diagnostic trials – identify more accurate or less invasive ways of diagnosing a particular disease in people who have signs or symptoms.
  • Treatment trials – test new treatments, new ways of giving existing treatments, or new combinations of treatments such as drugs, radiation therapy, surgery, nutrition, physiotherapy and complementary therapies.
  • Quality of life trials – designed to improve the comfort and quality of life of people who have cancer.

Learn more about:

Behavioural research

Behavioural researchers try to understand why people behave in the way that they do. They study people’s individual characteristics, lifestyles and social circumstances to see how these factors affect the risk of someone developing cancer or surviving cancer.

Researchers also look at how cancer impacts people emotionally and socially. Behavioural research does not focus on what causes cancer. This is studied in the field of epidemiology.

If you take part in a behavioural research study, you may need to fill in questionnaires or be interviewed about your lifestyle, including your eating, drinking, smoking, communication and exercise habits.

You may also need to participate in a program aimed at positively changing these behaviours. For example, you might be offered free counselling, an exercise class or a session on improving communication skills. The aim of the programs may be to reduce cancer risk or improve the way you cope with cancer.

Psychosocial research

One area of behavioural research is called psychosocial research. This looks at how cancer impacts people emotionally, psychologically and socially. In cancer care this is sometimes called psycho-oncology. Researchers try to understand how patients and carers cope emotionally at different stages of disease. They develop and test methods to improve people’s ability to deal
with these different issues.

Translational research

While it can take many years for research findings to become standard health care, there is pressure to use basic research to improve patients’ lives as fast as possible.

Translational research aims to get new treatments or medical approaches into practice quickly. It is sometimes called ‘bench to bedside research’ because basic research results are directly used to create new therapies and diagnostic tools.

Findings in the clinic can also influence research in the laboratory. This is called ‘bed to bench-side research’. For example, hospitals and health care professionals give information to researchers to help direct research into the most useful areas.

Often one institution oversees all aspects of a translational research project, from its beginnings in the laboratory to the rollout of a clinical trial and commercial development of a medicine.

Phases of a clinical trial

Clinical trials look for new ways to improve the diagnosis, treatment and management of people with cancer.

If a trial proves that a test or treatment is better than existing options, it may become the new standard care for patients in the future.

The majority of cancer clinical trials test anti-cancer treatments, particularly drugs, but also include radiation therapy and surgery. 

Researchers spend many years developing new treatments or medicines in the laboratory before involving people. They then plan the clinical trial to progress in a series of steps called phases. There are usually four phases, and information gathered in each phase determines whether the studies can move on to the next phase. 

There are also exploratory studies, sometimes referred to as ‘Phase 0 trials’ or ‘pilot studies’. These trials are less common, and are used to test how the body responds to an experimental drug before moving to Phase 1 trials. A small dose of the drug is given once or for a short time to a limited number of people.

If you are interested in participating in a clinical trial or another type of study, you can find out how to get involved and what happens during a clinical trial.


Participants 30 – 300
  • first study in people
  • tests safety of new treatment
  • finds the safest dose and the best way a treatment can be given
  • identifies side effects
  • studies how it works with other medicines or food (interactions)
How it works
  • participants are given a fixed dose and watched closely for side effects
  • if no side effects, dose is increased in next group of participants, this continues until significant side effects appear
Other info Patients sometimes benefit from having the new treatment but great improvements in their condition are uncommon.


Participants 10 – 40
  • builds on the results of Phase 1
  • continues to test safety of a drug
  • begins to assess how well a new treatment works on the disease
How it works
  • focuses on one cancer type
  • all participants receive the same experimental treatment
  • sometimes randomised controlled trial – i.e. participants are put into separate groups and given different treatments, which are then compared to see how well they treat the disease
Other info People often have treatment as an outpatient, but occasionally need to stay overnight in hospital for monitoring.


Participants 100s– 1000s
  • tests if the new treatment is better than the standard treatment
  • compares side effects, survival and quality of life
  • collects information that allows new treatments and existing treatments to be used in new ways or for different diseases
How it works
  • uses two treatment groups – experimental and control
  • usually groups are randomised and sometimes blinded
  • placebo may be used for comparison
  • runs over a long period of time
Other info New drugs go through two Phase 3 trials before they can be registered with the Australian Therapeutic Goods Administration (TGA) for use.


Participants 1000s
  • identifies how well treatment works when used more widely
  • monitors the long-term benefits and risks
  • looks for other uses of the drug or treatment
How it works
  • carried out after a treatment has been registered by the TGA
  • usually run by pharmaceutical companies that make the product
Other info Not all treatments go through Phase 4 studies. They are less common than trials in the earlier phases.
Read more phases of a clinical trial

Who works in clinical trials?

Cancer research is a large part of the health industry and offers many varied roles. If you join a study, you may have contact with some of these people:

Medical specialists, such as oncologists, haematologists and surgeons

  • supervise your treatment, follow-up and overall care.

Clinical trials nurse or research nurse

  • coordinates recruitment by talking to potential participants, making sure they are eligible and explaining the purpose of the trial
  • arranges appointments for tests, treatments or to see the specialist, and makes sure all paperwork is completed once you have agreed to join a trial
  • provides emotional support
  • acts as a link between the patient and the researchers or the health care team
  • may also be the main contact person 
  • larger clinical trials or hospitals have a dedicated clinical trials nurse, but smaller ones might not.

Marg (breast cancer)

Clinical trials or study coordinator

  • is similar to a clinical trials or research nurse, but instead of nursing qualifications they have a science degree or similar.

Allied health practitioners and complementary therapists

  • give treatment or advice in studies that investigate the use of non-medical treatments such as nutrition, physiotherapy, counselling, acupuncture or massage.


  • provides advice about medicines and monitors their effect on patients; does laboratory research.

Coordinating principal investigator

  • oversees research taking place at more than one study site, e.g. at multiple hospitals.

Principal investigator

  • has overall responsibility for conducting the trial at their hospital and ensuring patients are safe and the trial is properly run. This is usually a doctor with expertise in the field.

Researcher or investigator

  • develops and plans studies, and obtains, analyses and publishes results. Health researchers come from backgrounds such as medicine, science, psychology, allied health, consumer advocacy or complementary therapies.

Contact person

  • acts as the point of contact for all research participants if they have any queries or problems during a study. 
Read more about who works in clinical trials

This information was last reviewed in May 2015
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