What is blood cancer?

Updated 31 Jul 2017

Blood cancer happens when something goes wrong with the development of your blood cells. This stops them working properly and they may grow out of control. 

This can stop your blood doing the things it normally does to keep you healthy, like fighting off infections or helping repair your body.

Types of blood cancer

Updated 26 Jul 2017

The main types of blood cancer are:

There are also other blood cancers and related conditions that don’t fit within these groups such as myelodysplastic syndromes and myeloproliferative neoplasms.

Within these broad groups are many different blood cancers. Each specific type affects a particular type of blood cell and will have different symptoms, treatments and outlook (prognosis). You can find more detailed information about different types of blood cancer by selecting a type from the menu.

Acute and chronic blood cancers

You might see blood cancers described as either:

  • acute: this means an aggressive or fast-growing cancer that spreads quickly, or
  • chronic: this means a slower-growing or ‘indolent’ (lazy) cancer that takes longer to spread.

Childhood cancers

Some types of blood cancer affect both adults and children. The symptoms and treatments can be different between age groups, so you might see these described as a childhood or adult cancer.

How does blood cancer start?

Updated 26 Jul 2017

Cells are the tiny building blocks that our bodies are made of.  Every second of every day your body is refreshing your cells by making new ones and destroying old ones.

DNA is a substance within your cells.  It’s a kind of code that controls how cells develop, behave, and die. DNA is made up of small sections known as genes and packed into chromosomes in your cells.

If the DNA changes (mutates) in the stem cells that make your blood cells in your bone marrow, your blood cells might start to develop wrongly (abnormally), or fail to die when they should. These are the ‘cancerous’ or cancer cells.

The type of blood cancer you have generally depends on the type of blood cell that's affected.

  • Leukaemia happens when your leukocytes (white blood cells) become cancerous.
  • Lymphoma happens when your lymphocytes (a certain type of white blood cell) become cancerous.
  • Myeloma happens when your plasma cells (a type of B lymphocyte) become cancerous.

What causes blood cancer?

Updated 26 Jul 2017

All blood cancers are caused by faults in our DNA (mutations). In practically all cases these changes to our DNA happen for reasons we can’t explain and are linked to things we can’t control.

While in most cases we don’t know exactly what causes the changes to DNA that can lead to blood cancer, research has shown that there are a number of things that can affect how likely you are to develop certain types of blood cancer.

These ‘risk factors’ include:

  • age,
  • sex,
  • ethnicity,
  • family history,
  • radiation or chemical exposure, and
  • some health conditions and treatments.

The risk factors vary between the different types of blood cancer. For example, we know that myeloma only affects adults and is much more common in men and people from an African-Caribbean background, whereas Hodgkin lymphoma usually develops in people aged 15-25 or over 50, and people who already have problems with their immune system.

To find out more about the risk factors for a particular type of blood cancer, choose a type from the menu.

How does age affect my risk?

Generally as we age we’re more likely to pick up mutations / faults that can lead to blood cancer, meaning many blood cancers are more common in older people.

How does family history affect my risk?

While blood cancers are caused by problems in our DNA, in most cases this doesn’t mean blood cancer happens because the genes get passed down from parents to children (hereditary).

Although there’s some evidence for some blood cancers that having a family member with blood cancer slightly increases your risk, it’s not clear if this is because of a genetic (gene) fault passed down by parents, or for some other reason.

Does radiation cause blood cancer?

There’s some evidence that environmental factors such as radiation or chemical exposure may be linked to some types of blood cancer, but these would need to be at a much higher level than you'd experience in everyday life in the UK.

Is there anything I can do to prevent or lower my risk of blood cancer?

Unlike some other cancers, there’s no evidence to link lifestyle factors such as your diet or levels of exercise with blood cancer, which means there’s nothing you can do on a daily basis to help lower your risk of developing blood cancer.

Your blood

Updated 26 Jul 2017

Blood is your body’s transport, defence and communication system. It helps fight infection, carries nutrients (for energy), and sends messages around your body. Understanding how your blood and bone marrow work can help you understand what blood cancer is, how it affects your body, and how it’s treated.

Your blood is made up of blood cells, which are made in your bone marrow. Each type of blood cell has a particular job to do. If everything’s working normally, your body makes the right number of each type of cell to keep you healthy. If there are too many or too few of any type of blood cell, this can make you unwell.

What is blood for?

Your blood has many jobs:

  • Transport – it carries food, oxygen and proteins to different parts of your body. It also carries waste chemicals to your kidneys and lungs so they can get rid of them.
  • Defence – white blood cells are part of your immune system, which fights infections. This is the function that's most affected by blood cancer.
  • Communication – organs (such as your liver or stomach) release hormones into your blood which send messages to other organs.
  • Repair – blood contains cells and chemicals which can seal off damaged blood vessels and control blood loss.

What is blood made of?

Your blood is made up of white blood cells, red blood cells, platelets and plasma.

A diagram showing red blood cells, white blood cells and platelets in the blood inside of an arteryWhite blood cells (leukocytes)

These fight and prevent infection. There are five different types of white blood cell, which are lymphocytes, neutrophils, monocytes, eosinophils, and basophils.

There are some white blood cells that it can be helpful to know about when you’re finding out more about blood cancer:

  • T cells recognise infected cells and kill them or send instructions to that help your body to fight them. They’re sometimes called T lymphocytes.
  • B cells work with T cells to make antibodies that help clump around germs and trap them so other blood cells can come along and get rid of them. They’re sometimes called B lymphocytes.
  • Neutrophils are a type of granulocyte that helps the body fight bacterial infections. People with a lower number of neutrophils are more likely to develop bad infections more often and find it harder to fight them. 

Red blood cells (erythrocytes)

These contain a protein called haemoglobin, which carries oxygen from your lungs to all the tissues of your body. Your muscles, organs and other tissues need oxygen to produce energy from your food. It's more common to hear doctors talking about the concentration of haemoglobin in the blood than it is to hear them talking about the number of red blood cells.

Platelets (thrombocytes)

These stick together at the site of any tissue damage (like a cut) and stop bleeding.

Plasma

Blood plasma is the liquid part of blood that the blood cells move around in.

Bone marrow and how blood cells are made

Updated 26 Jul 2017

Bone marrow is a spongy material found in the centre of some of your bones, such as the back of your hips.

It's made up of blood vessels, fat, and tissue that makes blood cells (haemopoietic tissue).

How are blood cells made?

  • Blood cells start off in your bone marrow as a type of cell called a stem cell.
  • The stem cells then split (divide) to create either lymphoid stem cells or myeloid stem cells.
  • Lymphoid stem cells develop to form lymphocytes (white blood cells that help fight infections)
  • Myeloid stem cells go on to form red blood cells, platelets and other types of white blood cells.
  • They then move from your bone marrow into your blood and other parts of your body where they develop into fully grown (mature) blood cells.

Your body needs to keep constantly producing blood cells. It’s when something goes wrong with the development of your blood cells in your bone marrow that you may develop blood cancer.

If everything’s working normally, your body makes the right number of each type of cell to keep you healthy. If there are too many or too few of any type of blood cell, this can make you unwell.

Blood counts

Updated 26 Jul 2017

Everyone has slightly different numbers of each type of blood cell. If you’re healthy, the amount you have normally stays in the same range.

A ‘blood count’ is the term used to describe how many blood cells are in a sample of your blood.

What’s a normal blood count?

What’s considered a ‘normal’ blood range (blood count) can vary between different doctors, healthcare teams and hospitals, but as a general rule a healthy person is expected to have blood counts in the following ranges:

Type of blood cellNormal range for womenNormal range for men
Red blood cells  3.8 to 5 x 1012/l  4.5 to 6.5 x 1012/l
Haemoglobin* 115g/l to 165 g/l130g/l to 180 g/l
White blood cells4 to 11 x 109/l4 to 11 x 109/l
Neutrophils2 to 7.5 x 109/l2 to 7.5 x 109/l
Lymphocytes1.3 to 4 x 109/l1.3 to 4 x 109/l
Platelets150 to 440 x 109/l150 to 440 x 109/l

 *Doctors are usually more interested in the concentration of your haemoglobin than the number of cells in your blood, so haemoglobin is measured slightly differently.

How is my blood count worked out?

You’ll have a blood test.  A small sample of blood will be taken and checked under a microscope in a laboratory (this is known as a blood film).

Your immune and lymphatic systems

Updated 26 Jul 2017

Infections happen when a germ or germs enter your body and spread.

Your immune system

Your immune system is the network of cells, tissues and organs that help protect your body against infection by finding and killing germs. Blood cells such as B lymphocytes, T lymphocytes and neutrophils play an important role in fighting infection as part of your immune system.

Your lymphatic system

Your lymphatic system is also an important part of your immune system. It’s made up of:

  • Lymph vessels – a network of thin tubes that run around your body. They collect fluid called lymph and return it to your blood. Lymph contains lots of lymphocytes, which carry nutrients and remove bacteria from infected areas.
  • Lymph nodes / lymph glands – small lumps of tissue along the lymph vessels. As lymphocytes pass through the lymph nodes, they're changed and activated to fight infection. There are about 600 of these in your body.
  • Your spleen – a bean-shaped organ about the size of your fist above your stomach on your left side. It does some of the same work as the lymph nodes. It also filters out old or damaged cells from the blood stream and helps to fight infection.A diagram of the human body showing clusters of lymph nodes around the head, armpit and groin

How does blood cancer affect my immune and lymphatic systems?

  • If the blood cells that fight infection become cancerous, they don’t do their job properly and your body finds it much harder to fight infections.
  • Certain types of treatment such as chemotherapy can also put you at risk of infection because they kill off healthy blood cells that usually help to fight infections.

This means some people with blood cancer get more infections and they may be more serious. If this affects you, your healthcare team can let you know about the ways to reduce your risk.

Some types of blood cancer can cause problems with your lymphatic system – for example if you have lymphoma, abnormal lymphocytes may clump in your lymph nodes, causing noticeable swelling in your groin, armpit or neck. It may also cause your spleen to swell.

Worried that you might have blood cancer?

It’s important to remember that frequent infections and swollen glands can be caused by a variety of health problems.

Take a look at our advice on the signs and symptoms of blood cancer

Information and resources

Updated 26 Jul 2017

To help you find out more about blood cancer we’ve collated the external resources below. We don’t produce the information on these pages, so we can’t guarantee their content.

Blood and bone marrow

Blood components from NHS Blood and Transplant

The immune system

What is immunology? from the British Society for Immunology

Tests and investigations

Lab tests online – Department of Health approved website with details on tests and investigations

Incidence

QuickStats on incidence of blood cancers from the Haematological Malignancy Research Network

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