Glossary of clinical trials terms 

Cancer clinical trials can seem complex, especially if it’s your first time reading about them. We’ve compiled a glossary of words and phrases related to clinical trials to give you simple definitions of high-level clinical terms that you may come across. 

Term Definition
Ablation A procedure that destroys tissue in the body without surgically removing it. Ablation destroys cancer cells using chemicals, heat, cold or an electric current (radiofrequency). Ablation is a minimally invasive procedure that can be used as an alternative to surgery.
Active comparator A known, effective treatment used in a clinical trial to compare with the experimental intervention or treatment being investigated.
Adjuvant therapy A treatment given with, or shortly after, another treatment to enhance its effectiveness.
Advanced cancer Cancer that has spread and/or is unlikely to be cured.
Adverse event/effect An undesired effect of a drug, surgery or other intervention. May also be called a side effect.
Allied health professional A qualified professional who works with other members of the healthcare team to support a person's treatment and care. For example: psychologists, social workers, occupational therapists, physiotherapists and dietitians.
Anaemia A reduced amount of haemoglobin, the substance in red blood cells that carries oxygen in the blood. Anaemia can cause tiredness and fatigue, breathlessness and paleness.
Analgesic A drug that relieves pain.
Androgens Hormones responsible for the development of male sex characteristics, such as facial hair or a deep voice. Men and women both produce androgens. The most well-known androgen is testosterone.
Androgen deprivation therapy Treatment that involves blocking the production or action of testosterone. It is mainly used in the treatment of prostate cancer.
Angiogenesis The formation of new blood vessels. Tumours can use angiogenesis to create their own blood supply, which helps them to survive and grow.
Angiogenesis inhibitor A drug that stops new blood vessels from forming. Angiogenesis inhibitors can be used in cancer treatment to prevent tumour growth.
Antibody A protein made by the immune system that identifies and destroys infections and other potentially harmful 'invaders' in the body.
Anticoagulant A substance that prevents blood from clotting.
Antigen A substance that stimulates an immune response. When the antigen enters the body, the immune system creates an antibody to defend itself against it. Common antigens include viruses, bacteria, pollen and dust.
Arm A group of people receiving the same treatment in a clinical trial. Most clinical trials have two arms, but some have three or more arms.
Aromatase inhibitor A drug that reduces the amount of oestrogen in the body. Aromatase inhibitors are used in the treatment of some types of breast cancer, and may also be used to help prevent breast cancer.
Autologous From oneself or using cells or tissue from your own body. For example, an autologous stem-cell transplant is when a patient receives a transfusion of their own stem cells.
Baseline A starting point. In a clinical trial, the baseline marks the beginning for a patient before any intervention has occurred. Measurements are taken at baseline to record the participant's condition before the trial, then used for comparison over time to look for changes.
Behavioural intervention A type of supportive therapy that influences a person's behaviour, such as cognitive behavioural therapy (CBT). Behavioural interventions can help to manage and reduce stress associated with cancer and cancer treatment.
Bias Any factors that could influence the results of a clinical trial, other than the trial intervention itself. If a study is biased, its results are not reliable. Clinical trials use methods like blinding and randomisation to avoid bias.
Biopsy A medical test in which a small sample of tissue is removed from the body for examination or testing. Biopsies can be used to help doctors diagnose a disease or find out more information about it.
Biological therapy A treatment that uses substances made from living organisms to treat cancer and other diseases. These substances can be made by the body or in a laboratory. They work in different ways, but the main goal is to help the body's immune system to find and destroy cancer cells. Examples of biological therapy include immunotherapy, monoclonal antibodies and gene therapy.
Blinding Blinding is a method used to prevent bias in clinical trials. In a single-blinded study, the patient doesn't know which treatment or intervention they are receiving. In a double-blinded study, neither the patient nor the doctor knows which treatment is being given.
Bone marrow A soft, spongy material found inside bones. Bone marrow is where the body makes stem cells, and these stem cells develop into red blood cells, white blood cells and platelets.
Cancer A disease of the body's cells, where gene damage causes cells to multiply out of control. The cells may grow into a tumour and spread into surrounding tissue, and/or move to new sites around the body and form other tumours.
Cells The basic building blocks of the body. The human body is made of billions of cells that perform different functions.
Clinical research Research in which people (or their data or tissue samples) are studied to understand health and disease. Clinical trials are a type of clinical research.
Clinical trial Research studies that involve people. Each study tries to answer scientific questions and find better ways to prevent, treat or manage disease. Cancer clinical trials may be used to test new medicines, try new combinations of treatments, evaluate new ways of diagnosing cancer, or investigating other ways to improve the quality of life of people affected by cancer.
Chemotherapy A treatment that uses drugs to kill cancer cells, stop them from growing, or make them sensitive to radiation.
Combination chemotherapy Treatment that combines more than one chemotherapy drug.
Cohort A group of people in a clinical trial who receive the same treatment. Can also be called an arm.
Combination therapy/treatment Treatment that combines two or more different methods to treat a disease. For example, surgery + chemotherapy, or chemotherapy + radiation therapy.
Complementary therapy Treatments used alongside medical intervention to help manage symptoms and side effects.
Control arm/group The group of patients in a clinical trial that receives the control treatment (usually the best standard treatment available) and is compared with another group that receives the experimental treatment.
Control treatment The existing treatment being compared with a new or experimental treatment in a clinical trial. The control treatment is generally the best standard treatment available for that disease, which may be given alone or in addition to a placebo.
Cytotoxic drugs Drugs that damage or destroy cells. Cytotoxic drugs are used in chemotherapy to treat cancer by destroying cancer cells.
Diagnosis The identification and naming of a disease or other condition.
Diagnostic trial A clinical trial that studies or compares different tests and procedures used to diagnose a disease. Diagnostic trials try to find easier, faster or more accurate ways to detect and diagnose disease.
Decentralised clinical trial A type of clinical trial in which components of the trial are done away from a central research facility. Participants complete their clinical trial visit at a remote location, either through virtual tools, such as video calls and patient-reported electronic assessments, or by face-to-face interactions. Teletrials are a subset of decentralised clinical trials.
Detection The discovery of an abnormality or disease in the body. Early detection is the discovery of an abnormality at an early stage, when it is more likely to be cured.
Dose The amount of medication taken at one time.
Dose escalation Gradually increasing the dose of a new drug to find the best dose. Dose escalation is often done as part of a Phase I clinical trial, with a relatively small number of patients. This is often followed by dose expansion to learn more about the drug in large groups of people.
Dose escalation study A clinical trial that determines the best dose of a new drug or treatment. In a dose escalation study, the dose of the test drug is increased a little at a time, in different groups of people, until the highest dose that does not cause harmful side effects is found. A dose escalation study may also measure ways that the drug is used by the body.
Dose expansion Further testing of a new drug at the recommended dose. After dose escalation has been used to find the right dose, the drug is given to larger groups of people at this dose to better understand its effects. Phase I clinical trials often start with dose escalation and then move on to dose expansion to learn more about the drug.
Double-blind A double-blinded study is a clinical trial where neither the doctor nor the participant knows which treatment the participant is having. These trials are designed to prevent bias from affecting the results of the trial.
Eligibility criteria The rules for who can take part in a clinical trial. These rules are to ensure that the people taking part are similar in certain ways, so the results of the trial will be as reliable as possible. Eligibility criteria come in two parts: inclusion criteria and exclusion criteria.
Ethics The study of moral values or principles, including responsible conduct and what is fair.
Exclusion criteria The features that stop someone from taking part in a clinical trial. If a person meets any of the exclusion criteria, they are not eligible to participate.
Experimental arm/group In a clinical trial, the group of participants that receives the intervention or treatment being tested. Also called the interventional or investigational arm.
Experimental treatment The new or modified treatment that is being tested in a clinical trial.
First-line therapy The first treatment given for a disease. It is may part of a standard set of treatments, such as surgery followed by chemotherapy or radiation therapy.
Haematologist A doctor specialising in diseases of the blood.
Haematology The branch of medicine that studies the blood.
Hormone A substance in the body that helps to regulate and coordinate growth, metabolism and reproduction. Hormones are made in glands and carried in the bloodstream.
Hormone receptors Indicators on the surface of certain cells in the body that recognise and bind to specific hormones. Some cancer cells contain hormone receptors, which suggests that the cancer needs those hormones to help it grow, and therefore it may respond to hormone therapy.
Hormone therapy/treatment A treatment that targets hormones in the body. For example, treating certain types of cancers by blocking or reducing the levels of a hormone that the cancer cells need. Also called endocrine therapy.
Human Research Ethics Committee (HREC) A group that is designed to protect trial participants by reviewing and approving clinical trial protocols. The committee is made up of different people, including scientists, doctors, lawyers, and consumers. They make sure that a clinical trial is ethical and safe for patients before they allow it to go ahead.
Immune system A complex network of cells, organs and chemicals that defends the body from infection. The immune system is designed to recognise and attack foreign 'invaders', like viruses or bacteria, and abnormal cells like cancer cells.
Immunotherapy A treatment that stimulates or restores the ability of the immune system to fight infection and disease. Immunotherapy can be used in cancer treatment to boost the body's existing defences and help the immune system find and destroy cancer cells.
Inclusion criteria The features a person must have to join a clinical trial. If a person meets all of the inclusion criteria, and none of the exclusion criteria, they are eligible to participate.
Induction therapy The first treatment given for a disease. In cancer treatment the goal of induction therapy depends on the type of cancer. For example, induction therapy for acute leukaemia is intensive chemotherapy designed to achieve remission. For other cancers, the goal may be to shrink the tumour as much as possible before surgery or radiation. Induction therapy can also be called first-line therapy, primary therapy or primary treatment.
Informed consent The agreement to do something, or to let something happen, that is made with a full understanding of all the relevant information, including risks, benefits, and available alternatives. A person deciding to join a clinical trial, for example, should be given detailed information about the trial and have it explained to them in a way that they understand; they should have time to think about their decision, to discuss it with their doctor or family members, and to ask as many questions as they want.
Infusion A slow injection of a substance into a vein or other tissue.
Inoperable When something is unable to be removed or treated by surgery. May also be called unresectable or irresectable.
Intervention In medicine, a treatment, procedure, or other action taken to prevent or treat disease, or to improve health in other ways. In clinical trials, the intervention is the thing that is being tested by the trial. Examples include drugs, surgical methods, medical devices, diagnostic tests and behavioural interventions.
Intramuscular injection An injection into muscle.
Intratumoural Within a tumour. Intratumoural (or intratumoral) treatment means a treatment that is injected directly into a tumour.
Intravenous (IV) Into a vein. An intravenous drip gives fluids and/or drugs directly into a vein.
Intravenous (IV) infusion Giving fluid into the bloodstream through a drip. A bag of fluid connects to a length of plastic tubing and a needle, which goes into a vein, usually into the arm.
Investigator Another term for a researcher. There are usually a number of investigators involved in running a clinical trial, overseen by a principal investigator.
Laboratory A place where scientific experiments are carried out and new medicines are developed.
Laboratory research Research that is carried out in a laboratory to study tiny components of the body, including cells, compounds, and molecules.
Late-stage cancer Cancer that is far along in its growth and has spread to the lymph nodes and other parts of the body. May also be called stage 4 (or stage IV) cancer, advanced cancer or metastatic cancer. Late-stage cancers are usually harder to treat than early-stage cancers.
Localised cancer Cancer that is limited to the place where it started, with no sign that it has spread.
Locally advanced cancer Cancer that has grown in the part of the body it started in, and may have spread into nearby tissues or lymph nodes, but has not spread to other parts of the body.
Local recurrence When a cancer comes back in the same part of the body as the original cancer, or very close to it.
Longitudinal study A study done over a long period of time - often decades - with participants being asked the same questions or having the same tests periodically to assess how their health changes over time.
Maintenance therapy/treatment Treatment that is given to help stop cancer from coming back, after it has already been treated with initial therapy.
Malignant Cancerous. Malignant cells can spread (metastasise) and can eventually cause death if not treated.
Medical oncologist A doctor who specialises in treating cancer with drug therapies, such as chemotherapy, hormone therapy and immunotherapy.
Metastasis The spread of cancer from one part of the body to another. In metastasis, cancer cells break away from where they first formed, travel through the blood or lymph system, and form new tumours in other parts of the body. These tumours are called metastatic tumours or metastases. The metastatic tumour is the same type of cancer as the original (primary) tumour.
Metastatic cancer Cancer that has spread from where it started to a distant part of the body.
Monoclonal antibody A type of protein that can locate and bind to substances in the body and on the surface of cancer cells. Used to treat some types of cancer.
Monotherapy Therapy that uses one type of treatment, such as the use of a single drug, or radiation therapy or surgery alone, to treat cancer.
Multidisciplinary team (MDT) A team of health professionals who work together to discuss a patient's case and figure out how best to manage their treatment and care. This team may include surgeons, doctors, nurses, psychologists, dietitians and physiotherapists.
Mutation A change in the genetic material of a cell. This may occur spontaneously or be caused by something outside the cell (a mutagen).
Neoadjuvant therapy Treatment given before the primary treatment, such as chemotherapy or hormone therapy given before surgery. Similar to induction therapy.
Oestrogen A hormone responsible for female sex characteristics and for the development and regulation of the female reproductive system. Oestrogen is mainly produced by the ovaries.
Oestrogen receptor A protein on the surface of a cancer cell that suggests oestrogen helps the cancer grow. If cancer cells have oestrogen receptors, it means the cancer is more likely to respond to hormone therapy.
Oncologist A doctor who specialises in the study and treatment of cancer.
Oncology The branch of medicine concerned with the study and treatment of cancer.
Orally When medicines are taken by mouth, for example when tablets, capsules or liquids are swallowed.
Outcome A specific result or effect that can be measured. For example, outcomes of a particular treatment or intervention could be decreased pain, reduced tumour size, or improvement of other disease symptoms.
Palliative treatment Also known as palliative care or palliation, this treatment is aimed at providing relief from symptoms without trying to cure the disease. Although it is not curative, palliative treatment may increase survival and improve a patient's overall quality of life.
Parallel assignment A way of assigning the treatment or intervention in a clinical trial in which participants are allocated to different arms that all run at the same time (in parallel), with each arm receiving a certain treatment for the duration of the trial. For example, everyone in Arm A is given treatment A, everyone Arm B gets treatment B, and so on.
Participant A person taking part in a clinical trial. Participants in a cancer trial are usually people with cancer, but they can also be carers or family members, people at risk of cancer, or other people who have been affected by cancer.
Participant Information and Consent Form (PICF) A written document that explains what is involved in a clinical trial, to help participants decide if they want to join the trial. The document also includes a consent section that the participant signs if they agree to take part.
Phase The stage of a clinical trial, showing how far along in the research process it is. The phase describes the purpose of the clinical trial and how many people are involved. There are four main phases of clinical trials, and each one is designed to answer certain questions. Read more about clinical trial phases.
Placebo Something that looks like a medical treatment but has no real effect. For example, a sugar pill or a saline injection. Sometimes, people feel better after taking a placebo because they believe it works. This is called the placebo effect.
Placebo comparator An inactive treatment used in a clinical trial to compare with the experimental intervention or treatment being investigated. The placebo looks the same as the experimental intervention but doesn't have any active ingredients or beneficial effects. In cancer trials, a placebo is usually given in addition to standard treatment.
Placebo effect A phenomenon where a person having treatment starts to feel better or show signs of improvement, even if that treatment is a placebo (inactive). Researchers try to avoid the placebo effect in clinical trials, because it can interfere with the results.
Precancerous Relating to a condition or lesion that may develop into cancer if it is left untreated. Precancerous cells are abnormal cells that have an increased risk of becoming cancerous.
Prevention trial A clinical trial designed to look for better ways to prevent a disease in people who have never had the disease, or to prevent the disease from returning in people who have had it before. Approaches may include medicines, vaccines, or lifestyle changes.
Primary cancer The original cancer. At some stage, cells from the primary cancer may break away and travel to other parts of the body, forming secondary cancers.
Principal investigator (PI) The senior researcher (usually a doctor) who is responsible for conducting a clinical trial at their hospital or university.
Progesterone A hormone produced by the ovaries that plays an important role in menstruation and pregnancy.
Progesterone receptor A protein on the surface of a cancer cell that suggests progesterone helps the cancer grow. This means the cancer is more likely to respond to hormone therapy.
Prospective study Research that looks forward in time. Participants are observed or monitored over a period of time to see what will happen. Clinical trials are typically prospective studies.
Prostate-specific antigen (PSA) A protein made by the prostate. Tests of PSA levels are used to diagnose prostate cancer.
Protocol A document that describes all the details about a clinical trial, including its aims, methods, and the reasons for conducting it. The protocol sets out the plan for how the clinical trial will run.
Psycho-oncology A field of cancer care concerned with the emotional and social responses of people with cancer and their families.
Quality of life A person's comfort and satisfaction, based on how well their physical, emotional, spiritual, sexual, social and financial needs are met within the limitations of their health and personal circumstances. Clinical trials often include a quality of life assessment (such as a questionnaire) to find out how the participants are feeling in their day-to-day lives.
Quality of life trial A trial that tests ways to improve the comfort and quality of life of people who have cancer or other conditions.
Radiation Energy in the form of waves or particles, including gamma rays, X-rays and ultraviolet (UV) rays. This energy can injure or destroy cells by damaging their genetic material. Radiation therapy (also known as radiotherapy) uses radiation to destroy cancer cells.
Radiation oncologist A doctor who specialises in the use of X-rays and other forms of radiation to treat cancer, as well as other conditions.
Radiation therapist A health professional (not a medical doctor) who administers radiation therapy.
Radiation therapy The use of targeted radiation to kill or damage cancer cells so they cannot grow, multiply or spread. The radiation is usually in the form of X-ray beams. Also known as radiotherapy.
Randomisation A method used to prevent bias in clinical trials. People are put into two or more groups at random, and researchers cannot choose who goes into each group. The groups receive different treatments or interventions, and the results of the different groups are then compared.
Randomised controlled trial (RCT) A clinical trial in which people are put into different groups at random, to receive either the experimental intervention or the control intervention.
Randomly allocated In clinical trials, the process of putting people into groups by chance to prevent the results from being biased.
Recurrent cancer Cancer that has come back (recurred) after treatment, sometimes several years later. Recurrent cancer starts with cancer cells that the first treatment didn't fully remove or destroy. A tiny number of cells from the primary cancer may survive in the body, and gradually over time grow to form a tumour again.
Red blood cells Blood cells that contain a substance called haemoglobin, which carries oxygen in the blood.
Referral In healthcare, the act of a doctor sending their patient to another doctor for additional healthcare services. In a clinical trial, your doctor may need to refer you to a particular hospital where the trial is being conducted, in order for you to participate.
Refractory Stubborn or difficult to control. In medicine, 'refractory' is used to describe disease that does not respond to treatment. Refractory cancer refers to cancer that may be resistant to therapy or becomes resistant over time, so the treatment has stopped working.
Registry trial A trial that collects information from people with a particular type of cancer who are having routine treatment.
Relapse The return of a disease after a period of improvement or remission. This is also called recurrence (see 'recurrent cancer').
Remission When the signs and symptoms of a disease (such as cancer) reduce or disappear. This may not mean that it is cured.
Resection The surgical removal of part of an organ or another structure in the body. If something is able to be surgically removed, it is called 'resectable'.
Response Evidence that a particular treatment is working. For example, that the cancer is responding to treatment. Response is measured in different ways depending on the type of cancer. People taking part in a clinical trial will have regular scans and other tests to measure their response to the trial intervention.
Retrospective study Research that looks backwards in time, studying things that have happened in the past. For example, a retrospective study might use the medical records of a large number of people who all had the same disease, to identify possible risk factors for the disease.
Scan Another name for an image or picture taken of structures inside the body, that can be used to diagnose and examine a disease or abnormality. There are many types of scans, including CT scans (computerised tomography), MRIs (magnetic resonance imaging), PET scans (positron emission tomography), X-rays and ultrasounds.
Screening A health measure designed to identify early signs of a disease in people who might be at risk, so that the disease can be prevented or treated as early as possible. Screening programs are usually aimed a specific group of people (population) based on their risk factors.
Screening [in clinical trials] The process of checking whether a person is eligible to participate in a clinical trial. Screening may involve a medical history, physical examination, blood and urine samples, scans and other procedures, to make sure that the person meets all the eligibility criteria.
Screening trial A type of clinical trial that aims to find the best way to detect a disease or health condition, such as cancer, especially in its earliest stages.
Second-line therapy/treatment Treatment that is given after the first course of cancer treatment. This could be because the first treatment didn't work, or it stopped working after a while, or because the cancer came back some time after treatment.
Secondary cancer A cancer that has formed elsewhere in the body after some cells from the primary cancer broke off and travelled to a different location. Secondary cancers are also called metastases.
Sequential assignment A way of assigning the treatment or intervention in a clinical trial in which participants are allocated to arms one after the other (sequentially) to receive a certain treatment based on where the trial is up to. For example, Arm A is given the first treatment, then after a period of time Arm B is given the next treatment, and so on.
Side effect Unintended effect of a drug or treatment. May also be called an adverse effect.
Single-arm study A trial in which all the participants are given the same intervention or treatment.
Single-blind A single-blinded study is a clinical trial in which the doctor and the research team know which treatment the participant is being given, but the participant doesn't know.
Sponsor The organisation, institution or company responsible for developing, financing and managing a clinical trial, and for making sure that the trial meets all legal and insurance requirements.
Stage The level or extent of a cancer, from stage I to stage IV, which is used to describe how far the disease has progressed and whether it has spread from to other parts of the body.
Standard treatment / Standard of care The best treatment that is currently available, and that has been proven to be effective for a particular type of cancer.
Stem cell A stem cell is a 'parent' cell from which blood cells evolve. Stem cells grow in bone marrow.
Stem cell transplant A procedure that replaces stem cells when they have been destroyed by high doses of chemotherapy and/or radiation therapy. Replacing the stem cells after treatment helps the bone marrow recover and continue to produce healthy blood cells.
Subcutaneously / Subcutaneous Beneath the skin. For example, when a medication is given by subcutaneous injection.
Supportive care Care and support that aims to improve the health, wellbeing and quality of life of people living with cancer, as well as their family and carers.
Surgeon A doctor who specialises in performing surgery.
Surgery Treatment that involves an operation. This may involve removing or repairing body parts or inserting a prosthesis. Surgery often requires cutting into the body, but modern techniques, such as laparoscopic surgery, are less invasive.
Surgical oncologist A doctor who specialises in treating cancer with surgery.
Surveillance In medicine, closely watching a patient's condition but not treating it unless there are certain changes. Surveillance is also used to check for early signs that a disease has come back.
Systemic therapy Treatment that reaches and affects the whole body. For example, chemotherapy is usually a systemic therapy because it circulates through the bloodstream all around the body.
Targeted therapy A type of treatment that aims to reach a specific location instead of affecting the whole body, for example by targeting specific proteins on the surface of cancer cells. This means damage to other cells can be avoided.
Telehealth Healthcare appointments done by phone or video call instead of face to face.
Teletrial Where hospitals - regional, rural and city - share a clinical trial and work together to deliver it to their patients all at the same time. The entire medical team involved in the one trial use technology to closely communicate with each other as one big team. A teletrial is a type of decentralised clinical trial, and may also be referred to as a networked clinical trial.
Testosterone An androgen, or male sex hormone. Testosterone is the primary sex hormone produced by the testes and is also an important hormone produced by the ovaries. It promotes the development of male sex characteristics and controls libido.
Therapy Another word for treatment.
Tissue A collection of cells of similar type that make up an organ or structure in the body.
Translational research Research that is designed to convert results from the laboratory into real-world clinical practice, with the aim of providing new treatment options for patients as efficiently as possible.
Treatment trial A clinical trial that tests a new or modified treatment.
Tumour A new or abnormal growth of tissue that forms in or on the body. A tumour can be benign (not harmful) or malignant (cancerous).
Tumour marker A substance found in, or produced by, cancer cells, or a substance produced by other cells in the body in response to cancer. Tumour markers may be found in the blood or other bodily fluids, or in the tumour itself (for example, when a sample is collected via biopsy). Tumour markers can be measured to get more information about the cancer, such as how aggressive it is and what type of treatment it responds to. There are many different types of tumour markers. Some are associated with a specific type of cancer, and others are associated with multiple types of cancer.
Unresectable Unable to be surgically removed from the body.
White blood cells A type of blood cell in the body, also known as leucocytes (leukocytes), or immune cells. The white blood cells are an important part of the immune system and play a major role in defending the body against infection.

Victorian Cancer Registry Victorian Government

The Victorian Cancer Trials Link is supported by the Victorian Government through the Victorian Cancer Agency.


Cancer Council Victoria would like to acknowledge the traditional custodians of the land on which we live and work. We would also like to pay respect to the elders past and present and extend that respect to all other Aboriginal people.