Clinical trials help 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.

In the past, clinical trials were seen as a last resort for people who had no other treatment choices. Today, people often have the option of receiving their first cancer treatment in a clinical trial. If a new treatment proves effective or more effective than the current standard treatment, trial patients who receive it will be among the first to benefit.

The majority of cancer clinical trials test anti-cancer treatments, in particular drugs, but also radiotherapy and surgery.

The stages of a trial

Before involving patients in a clinical trial, researchers spend many years doing basic research to investigate and develop new medicines in the laboratory.

The researchers then plan the clinical trial to progress in a series of steps called phases. There are usually four phases. These phases allow researchers to build up reliable information about the treatment over a long period of time. Information gathered in each phase determines whether the study can move on to the next phase.

Phase 1 trial

  • Aim - The first step in testing a new treatment in people. Before this, the new treatment has only been tested in the laboratory. The main aim of a phase 1 trial is to show that a new treatment can be given safely. Researchers try to work out the best way a treatment can be given (e.g. by mouth or injection), as well as the safe dose. The study tests how the drug works with other medicines or food. These are called interactions. This lets researchers know whether the drug should be taken with or without food, or if the patient might have problems if they’re taking other medication.
  • Number of participants – Because less is known about the possible risks and benefits in a phase 1 trial, usually only 10-40 people participate. This helps protect patients in case the drug needs further work in the laboratory. Participants in phase 1 trials of anti-cancer drugs are usually patients who have already had all the other proven treatments for the type of cancer affecting them.
  • How it works – In the phase 1 trial, small groups of recruited patients (called cohorts) receive a fixed dose of the new treatment and are watched closely for any side effects. If there are no major side effects, the dose is increased in the next cohort of patients, and so on, until significant side effects start to appear. This indicates that the dose should go no higher and establishes a safe dose for future studies.
  • Other information - Participants may need to stay overnight in a hospital or clinical trials unit so that they can be closely monitored. Patients sometimes benefit from having the new treatment, but great improvements in their condition are uncommon. This is because only a small number of new drugs being tested prove to be major advances.

Phase 2 trial

  • Aim – A phase 2 trial continues to test the safety of a drug and begins to assess if a new treatment shows signs of working on the disease. The aim is to discover if a new treatment seems to work well enough to justify a larger study (phase 3 trial). Patients may benefit from the experimental treatment but this depends on the type and stage of the cancer, the type of treatment used, and other factors, some of which may be unknown.
  • Number of participants – Usually 30-300 people with the same type of cancer are involved.
  • How it works – Although the treatment may be effective for many types of cancer, a phase 2 trial focuses on one cancer type only. In most phase 2 trials, all patients receive the same experimental treatment. However, patients may be put into separate groups and given different treatments, which are then compared. This is called a controlled trial.
  • Other information – People often have treatment as outpatients, but occasionally they need to stay overnight for monitoring.

Phase 3 trial

  • Aim - A phase 3 trial is designed to determine whether a new treatment is better than the best available standard treatment by comparing their effects on survival, quality of life and side effects. These trials can be used to assess new treatments, or to improve how existing treatments are used in different ways or for different diseases..
  • Number of participants – A phase 3 trial recruits large numbers of patients, usually several hundred, and sometimes thousands, to reliably detect differences between the tested treatments. People from different countries often participate.
  • How it works – Patients are usually put into two treatment groups. One group receives the experimental treatment (e.g. a new drug or a new dose of an existing drug) – this is the experimental group. The other group receives the best standard treatment available – this is the control group. Sometimes when there isn’t an existing treatment for the cancer type or its symptoms, a treatment without any medical effect (a placebo) is used for comparison. Trials usually run over a long period of time, and the outcomes of both groups are compared.
  • Other information – Phase 3 trials of new treatments are sometimes called registration trials because if they are successful, the next step will be for the manufacturer of the treatment (often a pharmaceutical company) to apply for the treatment to be registered and made available to the public. Researchers need to show that a new drug is safe and effective in two independent phase 3 trials before they can apply for registration with the Therapeutic Goods Administration in Australia.
  • In phase 3 trials, the experimental and control groups are always randomised and sometimes blinded. This means that patients are randomly put into one of two groups, and they do not know which treatment they are receiving.

Phase 4 Study

  • Aim – A phase 4 study is conducted after a treatment has been registered for use by the TGA and doctors are able to prescribe it outside of clinical trials. These studies are usually run by the pharmaceutical companies that make the product. This helps the companies more fully understand how their treatment compares to other treatments that are available for the same condition. They may also discover that the new treatment is beneficial for other conditions.
  • Number of participants – Usually several thousand people from many countries take part in a phase 4 study.
  • How it works – Companies monitor the long-term effects of their drug, particularly unexpected side effects. They may also investigate other uses of their drug – for example, its effects in medical conditions other than the condition for which it was originally registered.
  • Other information – Not all treatments are put through phase 4 studies. They are much less common than trials in the earlier phases.

Approving and subsidising drugs

The Australian Department of Health and Ageing’s Therapeutic Goods Administration (TGA) approves drugs that are safe and effective for sale in Australia.

Decisions about the funding of new drugs require additional information, some of which is gathered in phase 4 studies. Manufacturers of new drugs that have been shown to be better and/or more cost effective than existing treatments can apply to list them in the Pharmaceutical Benefits Scheme (PBS) so that the cost of the treatment is largely funded by the Government. This process generally takes several months.

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:

Health professionals

  • medical specialists, such as an oncologist, haematologist or surgeon – Supervise your treatment, follow-up and overall care.
  • clinical trials nurse or research nurse – Coordinates recruitment and participation for
  • a clinical trial or other type of study and liaises with other health professionals. They may also be the contact person
  • clinical trials or study coordinator – Similar to a clinical trials or research nurse, except that they do not have nursing qualifications.
  • allied health practitioners or complementary therapists – Give treatment or advice in studies that investigate the use of non-medical treatments such as nutrition, physiotherapy, counselling, acupuncture or massage.
  • pharmacist – Involved in laboratory research and during a clinical trial to provide advice about medicines and monitor their effect on patients.


  • coordinating investigator – Oversees research taking place at more than one study site, e.g. at multiple hospitals.
  • lead researcher or principal (chief) investigator – Has overall responsibility for the scientific, administrative, financial and ethical aspects of a study, and reports the study results.
  • researcher or investigator – Develops and plans studies, and obtains, analyses and publishes results. Health researchers come from backgrounds such as medicine, science, consumer advocacy or complementary therapies.
  • contact person – Point of contact for all research participants if they have any queries or problems that arise during a study.

The clinical trials nurse

Not all clinical trials or hospitals have a dedicated clinical trials nurse, but the larger ones do. The clinical trials nurse plays a key role for trial participants. Most patients find it easier to communicate with one person about a trial, so the clinical trials nurse is usually their main point of contact.

  • Nurses may help to recruit patients by talking to potential participants, making sure they are eligible and explaining the purpose of the trial. They also let the patient and their family know what to expect and what to do if there are problems during the trial.
  • Once you have agreed to join a trial, the nurse arranges appointments for tests, treatment or to see the specialist. They also make sure all paperwork is filled in.
  • Nurses provide emotional support and act as a link between the patient and the researchers or health care team.
  • Sometimes, this role is done by someone who is not a nurse. In this case, they are called the clinical trials or study coordinator.

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