Home > Cancer Research Network > Patient Area > Cancer glossary

Cancer Glossary


This glossary has been put together as a guide to some of the terms and phrases used in cancer research.

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z


Adverse event
An adverse event is any unwanted condition following treatment, whether or not it is believed to have been caused by that treatment.

Adverse reaction
An adverse reaction is an unwanted effect caused by a drug or other treatment. It will usually be reported to a Data Monitoring Committee if it occurs during a randomised trial. A Suspected Unexpected Serious Adverse Reaction (SUSAR) is a serious adverse event that would not be anticipated for the patient group under study.

An arm is one of the treatment groups in a trial. If a trial is testing two treatments, there will be two ‘arms’. One arm of the trial might be the usual treatment.

Adjuvant therapy
Following surgery this is the treatment given, usually chemotherapy, hormone therapy or radiotherapy. It is given to increase the prospect of killing all cancerous cells.

Back to the top


Baseline measures
At the beginning of a trial a patient may be asked questions regarding medical history, how they are currently feeling, or they may have some tests before being given the treatment. These are called baseline measures and will allow the researchers to know where the patient is starting from, so they can tell at the end of the trial whether there has been any change.

Blinding and double-blinding
Blinding means that someone involved in the study is unaware of which treatment group a participant belongs to. In drug trials this is often the clinician prescribing the treatment and the trial participant (“double-blind”). Giving a placebo or dummy treatment is the usual means to achieve blinding. The aim is to avoid hopes and expectations about the treatment influencing the way the improvements and side effects are assessed.

Back to the top


Chief investigator (CI)
The chief investigator is the researcher in overall charge of a trial. The patient may never meet the chief investigator, especially if the trial is very large and taking place in several countries. But this person is responsible for the design of the trial and how it is run, as well as for analysing and reporting the results. He or she is helped by a trial steering committee and a data monitoring committee.

Clinical Trials Nurse (CTN)
The clinical trials nurse is the nurse who will assist the oncologist/haematologist with the care of a patient on a clinical trial.

Clinical Nurse Specialist (CNS)
A clinical nurse specialist is a nurse who specialises in one particular tumour site

Clinical trial
Clinical trials are research studies involving people that are designed to assess new treatments. They range from initial studies in healthy volunteers (phase I), through safety studies in small numbers of patients (phase II), to large-scale randomised trials to compare against the standard treatment (phase III) and long-term follow-up studies to assess rare side-effects (phase IV). No matter how promising a new drug, medical device or surgical procedure may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known, and before it is approved for use.

Cohort study
A research method concerned with observing events involving a particular group of people over time (such as a group of patients’ progress in long term treatment) in order to provide information which is useful for identifying longer term strategies or identifying groups of participants at higher risk of adverse outcomes.

Control group
Most clinical trials include a control group. If you are part of the control group you will not receive the treatment being trialled. Instead, you’ll receive the usual treatment, with or without the addition of a placebo. This enables comparison of the outcomes of the two treatments and decides whether the trial treatment is better or not.

Back to the top


Data monitoring committee
Most randomised trials have a data monitoring committee that follows the progress of the trial and makes sure it is ethical to continue. The people on the data monitoring committee are independent, in that they should not be employed by the institutions (universities and hospitals) that are running the trial. If they think that people are experiencing serious or unexpected side effects, or if evidence has emerged that one of the treatments being compared is clearly better than the others, they can advise that a trial is stopped.

Department of Health (DOH)
The DoH sets national standards in health and social care.

Double-blind trial
If you take part in a ‘double-blind’ trial, neither you nor your doctor will know which treatment you are receiving. The aim is to make sure that nobody’s expectations affect the results of the trial. (See blinding).

Back to the top


The extent to which something improves outcomes under ideal circumstances. It has a positive measurable effect overall when taken by people meeting the eligibility criteria receiving the treatment exactly as prescribed.

Eligibility criteria
All trials have guidelines about who can take part. These are called ‘eligibility criteria’, consisting of inclusion criteria and exclusion criteria.

Ethics committee
The job of an ethics committee is to make sure that research carried out in the NHS respects the dignity, rights, safety and well-being of the people who take part in medical research. A trial that takes place within the NHS cannot go ahead if an ethics committee has not approved it, and the protocol for a trial cannot be changed without the approval of the ethics committee. Ethics committee members include researchers and healthcare professionals as well as members of the public.

Exclusion criteria
Exclusion criteria determine who won’t be able to join a trial – for example, many trials exclude women who are pregnant, or who may become pregnant. This avoids any possible danger to a baby. Trials will also exclude people who are already taking a drug that may interact with the treatment being studied.

Back to the top




A doctor who specialises in blood disorders.

Back to the top


Inclusion criteria
Inclusion criteria help researchers decide who can join a trial. For example, some trials only include people of a certain age, or at a particular stage in their illness. You may have to have a medical examination before a trial (e.g. a blood test) to assess whether you are suitable to take part. (See also eligibility criteria).

Informed consent
You cannot be entered into a trial without signing a form saying that you have given your informed consent. The only exception would be in extreme circumstances, for example, if you’re admitted to hospital in an emergency and you’re unconscious. If you sign this form, you are saying that you believe you have been given all the important facts about a trial, you understand them and that you have decided to take part in the trial of your own free will. Even after giving your informed consent, you are free to withdraw from the trial at any time without giving a reason and without it having an impact on your healthcare.

The Mental Capacity Act 2005 has strict rules about entering people into a trial without informed consent – researchers must consult a carer or nominated person, and if these cannot be found, and it is urgent to enter the person into a trial, they must have the agreement of a registered practitioner who is not involved in the research project.

Back to the top





Medical Research Council (MRC)
The UK Medical Research Council is a national organisation funded by the UK taxpayer. It funds and supports research in many areas with the aim of improving the health and quality of life of the UK public and contributing to the wealth of the nation.

The Medicines and Healthcare products Regulatory Agency (MHRA)

The MHRA is a part of the Department of Health. Its job is to protect and promote public health and patient safety by ensuring that medicines, healthcare products and medical equipment meet appropriate standards of safety, quality, performance and effectiveness, and are used safely.

Back to the top


The National Institute for Health and Clinical Excellence (NICE) is part of the NHS. NICE decides whether a new treatment should be made available on the NHS and publishes guidelines on the best treatment for various conditions. NICE looks at the results of clinical trials and decides if there is enough evidence from trials to show that:

  • A new treatment is better than existing treatments
  • The benefits of the new treatment outweigh the costs of its side effects and of making it available
  • The treatment is cost-effective in terms of practical benefit versus cost to the NHS.

Back to the top


A doctor who specialises in treating cancer.

Back to the top


Palliative care
Palliative care concentrates on improving your quality of life and that of your family. It focuses on controlling pain and other symptoms, and meeting a person's social, emotional and spiritual needs.

Patient Information Sheet (PIS)
Trial specific information given to a patient for them to consider whether to take part in the trial.

Peer review
Research proposals and results are usually reviewed by a number of people who are independent of the researcher who designed the study but who nevertheless have an interest in research in the same disease area so that data, information and methods can be verified from a range of perspectives. Consumers often act as peer reviewers. They may not feel able to comment on the research method but will have very valuable views about whether the research topic is an important one for consumers, and whether the research involves consumers in an appropriate way.

A placebo is a fake or dummy treatment. It allows researchers to control for the ‘placebo effect’. This is a psychological response where people feel better even though the treatment they are receiving is not working. By comparing people’s responses to the placebo and to the treatment being tested, researchers can tell whether the treatment is having any benefit over and above the placebo effect. Placebos are designed to have no pharmacological effect but they may make people better.

Principal investigator
The principal investigator is the researcher in overall charge of a trial at a particular site.

A protocol is the plan for the trial and it must include information on:

  • What question the trial is asking
  • How many people will be involved
  • Who can take part in the trial - the eligibility criteria
  • What treatments will be compared
  • What tests people taking part in the trial will have and when they will have them
  • Details about how and when information will be collected

The protocol is often long and technical as it describes in great detail what the researchers must do during the trial. This is the document they continually work from. It cannot be changed without going back to a research ethics committee for approval.

Back to the top


Quality of life measure
Researchers sometimes use a scale to measure someone’s quality of life. The measures most often used are ‘quality adjusted life-years’ (QALYs) and ‘disability adjusted life-years’ (DALYs) and are based on the number of years’ life that would be added by a certain intervention.

Another measure which is growing in popularity is the EQ-5D. This scale looks at 5 areas of health (mobility, self-care, usual activities, pain and anxiety or depression) and asks the participant to comment on whether they have no problems, some problems or extreme problems with these areas.

Quality of life studies (QoL)
As well as measuring the physical effects of a treatment (for example changes to your blood pressure), many trials now try to assess the impact of treatments on people’s quality of life. For example, a ‘quality of life’ study might ask you about:

  • Your mood and general sense of well-being
  • Whether you feel more tired than usual
  • Whether you are managing to do more things than before
  • Whether you feel more like socialising
  • Whether your sleep patterns have changed.

Back to the top


Randomised controlled trial (RCT)
Most phase III and many phase II clinical trials are randomised controlled trials. Before you take part in a randomised trial, your doctor will have determined that either treatment offered by the trial may be appropriate for you. The decision as to which treatment is allocated will be random, as if by the toss of a coin. In practice, rather than a coin it is usual to use a computer program so that decisions can be recorded and audited.

Randomisation is the only way to ensure that there is a fair comparison between treatments. As every individual has the same chance of receiving the experimental treatment, the groups of people will be broadly similar.

Randomisation is important to ensure that the results of a clinical trial are not affected by allocation bias. It is quite easy for people to be biased without realising it. For example, suppose a new treatment is being tested that has quite bad side effects. Without randomisation, researchers, doctors and the sickest patients might avoid the new treatment. As the trial continued, more and more of the sickest patients would join the comparison group getting the old treatment, so this group would then have more and more of the sickest patients in it. The people in the new treatment group might do better simply because they were not as ill when they started the treatment. These results could be interpreted wrongly – people might believe that the new treatment worked better than the old one. Randomising patients to different treatment groups avoids biasing the results in this way.

The treatment of cancer using radiation (x-rays, gamma rays etc) to destroy cancer cells.

Back to the top


Serious adverse reaction (see also adverse reaction)
An adverse reaction is described as “serious” if it is life-threatening or it results in on of the following outcomes:

  • death
  • hospitalisation
  • permanent disability
  • birth defects

Side effects (see adverse reaction)
Side effects, or adverse reactions, are undesired effects of a treatment. For example, if you are given a drug to treat a mental illness and it makes you sick, the sickness would be described as a side effect. Clinical trials will often look at the short-term and long-term side effects of a treatment. Sometimes side effects can be beneficial. For example, Viagra was developed to treat blood pressure and its current use was discovered as a side effect.

Back to the top


Topic Specific Research Networks
This term is used to distinguish the networks dealing with a particular disease area or area of practice (e.g. Cancer Research Network) from the Comprehensive Research Networks.

Trial Steering Committee (TSC)
Most trials have a trial steering group or committee. This is to ensure the trial is running well and to receive advice from the Data Monitoring Committee. In the UK, the TSC is usually chaired by an independent expert clinician or researcher, and attended by a number of independent experts and service user or carer representatives as well as by those leading the research.

Back to the top






Back to the top

Source: 2008 Stroke Research Glossary
Acknowledgement to:

  • NW Stroke Local Research Network
  • NW LRN
  • Jo Stevens

Research NetworkResearch