Understanding cancer terminology

Expert reviewer, Dr Adam Dangoor, Consultant Medical Oncologist
Next review due June 2020

If you have cancer, you may hear medical terms that you don’t understand. At appointments and during treatment, it may even sound like a foreign language at times. So we’ve put together a list of some common cancer terms with explanations of what they mean.

A - D

Adjuvant therapy

A treatment that you have after your initial treatment for cancer. For example, chemotherapy after surgery. The aim of adjuvant therapy is to try to reduce the chance of the cancer from coming back. Adjuvant therapies include chemotherapy, radiotherapy, hormone therapy and biological therapy. See also ‘neoadjuvant therapy’ below.

Advanced cancer

If your doctor describes your cancer as 'advanced', it usually means that it's spread from where it started to another part of your body. Locally advanced cancer usually means that the cancer has grown from where it started into nearby body tissues or lymph glands. See also ‘Stage’.

Aggressive cancer

This is an informal term rather than a medical one. If your doctor describes your cancer as aggressive, it means it tends to grow quite quickly. The medical term that describes how quickly or slowly a cancer is likely to grow is grade. See also ‘Grade’.


This means a tumour isn’t cancer (is not malignant). Benign tumours usually grow quite slowly and don’t spread. They usually only cause problems if they grow very large, or press on other organs in your body. They can also affect you if they take up space inside your skull or release hormones.

Biological therapy

Treatments that are (or are developed from) natural body chemicals. They may act on cancer cells directly to kill them or stop them growing. Or they may help the immune system to fight back against and kill cancer cells. Types of biological therapies include monoclonal antibodies, cancer growth inhibitors, vaccines, gene therapy and immunotherapy. They work in lots of different ways; for example, changing how cancer cells send growth signals to each other, or stopping cancers from growing new blood vessels.


A small sample of tissue taken from your tumour, either in surgery or using a needle. A histopathologist is a doctor who specialises in examining samples of tissue to help diagnose diseases. They’ll examine the sample under a microscope to see if it contains any cancer cells and if so, what type.


Something that is known to cause cancer, for example, tobacco smoke. Not everybody exposed to a carcinogen gets cancer so there are other factors that can play a part, such as your age, diet and genetic make-up.


Most cancers are carcinomas. They are cancers that start in cells of tissues that cover and line the body cavities and organs (epithelial cells).

Carcinoma in situ

A very early stage of cancer, where the cancer cells are only found in the place where they started growing in the body. So the cancer hasn’t spread to anywhere else in your body. Sometimes called stage 0 cancer.


Treatment with drugs that kill cancer cells. Chemotherapy works by killing cells that are dividing into two. Cancer cells divide more often than normal cells.

E - F


Describes how cancer cells look under a microscope. The more abnormal they are, the higher the grade. Low grade cancers tend to grow more slowly and be less likely to spread. Cancers are most often graded from one to three, or one to four.

Hormone therapy

Treatments that block the production of a hormone in your body, or stop a hormone from working. Examples include treatment that blocks testosterone production in prostate cancer and treatment that stops oestrogen from working in breast cancer. Also called endocrine therapy.

I - L


A type of biological therapy that uses the immune system to fight cancer. See also ‘Biological therapy’.


A cancer of white blood cells that starts in the bone marrow. There are several different types of leukaemia, affecting different types of white blood cell.


Cancer that starts in cells of the lymphatic system. There are two main types: Hodgkin lymphoma and non-Hodgkin lymphoma.

Lymph glands (nodes)

Glands found throughout the body that are part of the immune system. Cancer can start in the lymph glands (lymphoma). More commonly, it spreads to the lymph nodes from a cancer that started somewhere else in the body.

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M - P


Another word for cancerous and the opposite of benign. A malignant tumour (cancer) grows more quickly than a benign tumour and can spread to other parts of your body.


A type of cancer that starts in pigment cells in the skin (melanocytes), either in a mole or in normal looking skin. Melanoma is the most serious form of skin cancer but can be cured if it’s removed before the cancer cells have spread.

Metastatic cancer

Cancer that has spread from one part of the body to another. It’s also called secondary cancer.


A type of bone marrow cancer that starts in cells called plasma cells.

Neoadjuvant therapy

Treatment you have before your main treatment, which is usually surgery. The aim of the treatment is usually to try and shrink the cancer to make it easier to remove and to help reduce the risk of the cancer coming back in future. Neoadjuvant therapies include chemotherapy, radiotherapy and hormone therapy.


Another name for an abnormal lump of cells (a tumour). A neoplasm can be non-cancerous (benign) or cancer (malignant).

Palliative care

Also known as supportive care, palliative care is treatment designed to help control symptoms and improve quality of life. Palliative care is often used to mean treatment for people whose illness can’t be cured, but this is not necessarily the case.

Personalised medicine

Treatment that is tailored to the biology of your specific cancer. For example, your cancer cells may have too many of a particular growth receptor, so your doctor may choose to give you a medicine that blocks that receptor. Many biological therapies can be used as part of personalised medicine. See also ‘Biological therapy’.

Primary cancer

Where your cancer originally started in the body. If a cancer has spread, this is a secondary cancer. So, lung cancer that has spread to your liver is primary lung cancer with secondary cancer in your liver. See also ‘Secondary cancer’.


The likely outcome of your cancer. It could refer to your chance of recovery, the likelihood of your cancer coming back or, if your chance of survival is low, how long you might expect to live for.

Q - T


Treatment using high energy radiation to kill cancer cells; for example, X-rays, gamma rays or protons. You most often have radiotherapy treatment from a machine outside the body, but it can also be delivered internally from implants (called brachytherapy) or radioactive injections or drugs.


When a cancer is in remission, there is no sign of it in examinations or tests. Doctors tend to talk about remission instead of cure because cancers can sometimes come back. In a partial remission, some, but not all, signs and symptoms have gone.


A type of cancer that starts in the cells of bone or other tissues that support the body, including muscle, blood vessels, cartilage and fibrous tissues.

Secondary cancer

A cancer that has spread from where it started. Some of the most common places for secondary cancers are bone, liver and lung. Where a cancer is most likely to spread depends on what type of primary cancer it is. See also ‘Primary cancer’.


A system that doctors use to describe the size of your cancer, how far it has grown and whether it has spread. This helps your doctor to choose the best treatment for you. There are usually four stages. Stage one means that the cancer is small and very localised. Stage four means the cancer has spread. There are other staging systems such as the TNM classification, which is used to describe what the tumour is like, including its size and if it has spread to your lymph nodes or to other places in your body.

Systemic therapy

A treatment that travels through the bloodstream and so reaches your whole body. All drug treatments that are injected or that you take by mouth are systemic, including chemotherapy, biological therapy and hormone therapy.

Targeted therapy

A type of treatment that directly targets cancer cells to stop them from growing and spreading. Targeted treatments are a type of biological therapy. See also ‘Biological therapy’.


A lump of cells that may or may not be cancerous (malignant or benign). A tumour is also known as a neoplasm.

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Related information

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    • NCI Dictionary of Cancer Terms. National Cancer Institute., accessed May 2017
    • A guide for patients with advanced cancer. European Society for Medical Oncology., published 2011
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    • Self study module 8: clarifying diagnosis and prognosis. Education in palliative and end-of-life care for oncology (EPECTM-O)., accessed August 2017
    • Biological therapies for cancer. National Cancer Institute., reviewed June 2013

  • Reviewed by Laura Blanks, Specialist Health Editor, Bupa Health Content Team, July 2017
    Expert reviewer Dr Adam Dangoor, Consultant Medical Oncologist
    Next review due July 2020

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