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Cancer Clinical Trials

Glossary & key terms

Our glossary is designed to help explain some of the terms used when discussing cancer research, radiation therapy or cancer clinical trials. Your doctor or oncologist can also help you to further understand these terms.


The accumulation of trial participants registered on a cancer clinical trial.

Approved for activation

This means that a trial has met all the requirements of the trial development phase (as determined by TROG Cancer Research), has been allocated a TROG Cancer Research number and given permission to begin the process of submission for ethics review and approval to commence accruing patients.

Approved for development

The phase that commences when a new proposal receives the endorsement of TROG Cancer Research (based on scientific merit); successfully completes a feasibility assessment; and is approved by the TROG Cancer Research Scientific Committee as appropriate for further development.


Any of the treatment groups in a randomised trial. Most randomised trials have two or more arms.

Australian New Zealand Clinical Trials Registry (ANZCTR)

A publicly accessible online listing (register) of clinical trials being undertaken in Australia and New Zealand. Available at


A randomised trial is blind if the trial participant is not told which arm of the trial they are on and is therefore unaware of whether they are in the experimental or control arm of the trial; also called masked.

Cancer research trial

A cancer research trial, or clinical trial, is a study of recruited patients to determine whether a new or existing cancer treatment is safe and effective or can be improved. 

Closed (to accrual)

A trial is considered closed (to accrual) after the last participant has been recruited and trial participants are in the follow-up phase.


A trial is considered completed when trial participants are no longer being examined or treated (i.e. no longer in follow-up); the database has been ‘locked’ and records have been archived.

Control group

The standard by which experimental observations are evaluated. In many clinical trials, one group of trial participants will be given an experimental drug or treatment, while the control group is given a standard treatment for the illness.

Efficacy (of a drug or treatment)

The maximum ability of a drug or treatment to produce a result regardless of dosage. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed.

Eligible patient

Means a patient selected in accordance with, and who meets, the eligibility criteria specified for the trial.

Eligibility criteria

The clinical and demographic characteristics that define those participants eligible to be enrolled in the trial.

Ethics approval

Approval given by a Human Research Ethics Committee (HREC) for a clinical trial to be conducted with patients.


A process of periodic contact with participants enrolled in a trial for the purpose of monitoring health status, administering trial treatments, modifying the course trial treatment, observing the effects of the trial treatment, or for data collection.

Good clinical practice (GCP)

A standard for the design, conduct, performance, monitoring, auditing, recording, analyses, and reporting of clinical trials that provides assurance that the data and reported results are credible and accurate, and that the rights, integrity, and confidentiality of the trial participants are protected.

Inclusion/exclusion criteria

 The medical or social standards determining whether a person may or may not be allowed to enter a clinical trial. These criteria are based on factors including age, gender, the type and stage of a disease, previous treatment history and other medical conditions. It is important to note that inclusion and exclusion criteria are not used to reject people personally, but rather to identify appropriate trial participants and keep them safe.

A process by which a patient voluntarily confirms their willingness to participate in a particular trial, after having been informed of all aspects of the trial that are relevant to the patient’s decision to participate. Informed consent is documented by means of a written informed consent form (which has the name of the trial clearly displayed). It must be signed and dated by the trial participant (or the trial participant’s legally acceptable representative) and the Investigator, in the presence of each other.

Intergroup trial

A clinical trial which is supported by two or more collaborating clinical trials groups according to a single protocol. An intergroup trial requires a Trial Coordinating Centre which will support the administrative requirements of the research and perform central data collection and analysis.


The act of overseeing the progress of a clinical trial, and of ensuring that it is conducted, recorded, and reported in accordance with the protocol, standard operating procedures, good clinical practice, and the applicable regulatory requirement(s).

New proposal

A new trial either at concept stage or with a fully developed protocol submitted for consideration and approval of TROG Cancer Research, and to be carried out under the auspices of TROG Cancer Research.


The general questions the trial was designed to answer. May be associated with one or more hypotheses that, when tested, will help answer the question.


A trial is considered open after the first trial participant has been registered.

Outcome (primary and secondary)

An outcome variable of interest (also called an end point). The primary outcome is of greatest importance. Data on secondary outcomes are used to evaluate additional effects of the intervention.

A detailed written description of all aspects of the trial and accompanying consent form.


A person who is receiving medical attention, care, or treatment.

Phase I trials

The first step in testing a new treatment in humans. These trials test the best method of administration and the best dose.

Phase II trial

A trial to study the safety, dosage levels, efficacy, and response to a new treatment.

Phase III trial

A trial to compare the results of people receiving a new treatment with the results of people receiving the standard treatment (e.g. which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment is seen to work in phases I and II trials. Phase III trials may include hundreds of people.

Phase IV trials

After a treatment has been approved and is being marketed, it is studied in a phase IV trial to evaluate side effects that were not apparent in the phase III trial. Thousands of people are involved in a phase IV trial.


A substance not containing an active agent under study, administered to some trial participants to compare the effects of the active agent administered to other trial participants.

Principal investigator (PI)

The person responsible for the conduct of the clinical trial at a trial site. If a trial is conducted by a team of individuals at a trial site, the PI is the responsible leader of the team.

Quality assurance (QA)

The planned and systematic actions that are established to ensure the trial is performed and the data are generated, documented (recorded), and reported in compliance with good clinical practice and applicable regulatory requirement(s).

Quality control

The operational techniques and activities undertaken within the quality assurance system to verify that requirements for quality of the trial-related activities have been fulfilled.

Quality of life (QOL)

A broad-ranging concept that incorporates an individual’s physical health, psychological state, level of independence, social relationships, personal beliefs, and their relationships to salient features of the environment.

Radiation medicine

is the overarching specialist branch of therapies used to treat and eliminate cancer.

Radiation therapy

Radiation therapy describes the treatment procedure performed by trained medical professionals.


The process of assigning trial participants to treatment or control groups using an element of chance to determine the assignment to reduce bias.


 Process used by investigators to find and register eligible participants onto a clinical trial.


The act of assigning a trial participant with a unique trial identification number.


Means all results and/or data obtained within the framework of the trial.

Sample size

The number of participants calculated for a clinical trial which considers potential drop-out rates of participants and calculates the number of participants where a change is needed to be observed to achieve the trial’s aims and objectives.


Any individual member of the clinical trial team, designated and supervised by the Principal Investigator at a trial site to perform critical trial-related procedures and/or to make important trial-related decisions (e.g. associates, residents, research fellows, registrars).


A sub-study is essentially an add-on study to the main protocol, designed to ask a separate research question and which includes new data collection from some or all the trial participants participating in the main protocol.


Recruiting or enrolling trial participants to a clinical trial has halted prematurely but potentially will resume.


Recruiting or enrolling trial participants to a clinical trial has halted prematurely and will not resume; trial participants may or may not be continuing with examinations or treatment.

Trial Chairperson

The Investigator assigned the overall responsibility for the development and coordination of a multicentre clinical trial.

Trial Coordinating Centre (TCC)

Means the site, facility or clinical research organisation appointed by the Trial Chairperson to carry out trial development, trial initiation, data management procedures including maintenance of the trial database, liaison with trial sites participating in the trial, randomisation services and statistical analysis.

Trial participant

An individual who participates in a clinical trial, either as a recipient of the investigational product(s) or as a control (receiving standard care). This term can be used interchangeably with ‘Trial patient’.

Trial registration number

A unique identifier assigned at the time of registration to each trial participant to protect the participant’s identity and used in lieu of the participant’s name when adverse events and/or other trial related data are reported.

Trial site

The location(s) where trial-related activities are conducted (usually within the hospital or other institution where the Principal Investigator is based).