What is blood cancer?

Blood cancer refers to a group of cancers that can affect your bone marrow, blood or lymphatic system (part of your immune system). They all affect the development of your blood cells and usually don’t cause solid tumours to form. There are different types of blood cancer. They include:

Leukaemia

Leukaemia develops in your bone marrow, the spongy material inside your bones where your blood cells are made. In healthy bone marrow, stem cells within it develop into mature red blood cells, white blood cells or platelets (fragments of cells responsible for blood clotting). These cells are then released into your bloodstream. 

In leukaemia, the stem cells develop abnormally and a large number of immature cells or abnormal white blood cells are released into the blood. This makes it harder for the bone marrow to produce red blood cells and platelets. Doctors classify leukaemia based on the type of cells involved — either myeloid cells or lymphocytes — and how fast it progresses.

There are four types of leukaemia:

Acute myeloid leukaemia (AML)

This is the most common type of leukaemia and affects both adults and children. As the name suggests, AML affects myeloid cells and develops rapidly. Symptoms include feeling breathless, tired or weak, looking pale, catching infections often, frequent and unusual bruising or bleeding (eg frequent nosebleeds or bleeding gums) and unintentional weight loss. 

Acute lymphoblastic leukaemia (ALL) 

ALL usually affects children, most often under the age of 15. It progresses rapidly and affects lymphocytes. It shares many of the same symptoms discussed earlier for AML. However, additional symptoms for ALL include a purple skin rash (purpura), bone and joint pain, fever, night sweats, swollen lymph nodes and tummy pain. 

Chronic myeloid leukaemia (CML)

CML occurs mostly in adults, progresses slowly and affects myeloid cells. It shares common symptoms with other types of leukaemia, including breathlessness, easily bruising and bleeding, frequent infections, pale skin, tiredness and unintentional weight loss. Other symptoms include bone pain, feeling full after only eating a small meal, fever, night sweats, and swelling and tenderness on the left side of your tummy. 

Chronic lymphocytic leukaemia (CLL)

CLL mostly affects people aged over 60, progresses slowly and affects lymphocytes. As with other types of leukaemia, symptoms include frequent infections, easily bruising and bleeding and unintentional weight loss. Other symptoms include anaemia, fever, night sweats, swelling and tenderness in your tummy, and swollen lymph nodes in your neck, armpits or groin. 

Lymphoma

Lymphoma affects lymphocytes, the same white blood cells affected in ALL and CLL. However, in leukaemia, the cancer develops in the bone marrow, while in lymphoma, the cancer develops in the lymphatic system, which includes lymph nodes and lymphatic vessels. The abnormal lymphocytes can’t effectively fight infection as healthy lymphocytes do. Symptoms include swollen lymph nodes and frequent infections.

Myeloma

Myeloma develops in your bone marrow and affects plasma cells. Plasma cells are part of your immune system and make antibodies to fight infections. In myeloma, these plasma cells produce abnormal antibodies that can’t fight infection and instead build up and damage your tissues, particularly your kidneys and bones. Symptoms, therefore, include frequent infections, achy, weak bones and kidney problems.

Myelodysplastic syndrome (MDS)

MDS is a rare blood cancer that usually affects adults aged over 70. It starts in your bone marrow and prevents it from making enough healthy blood cells. Instead, abnormal blood cells are produced that aren’t fully developed. It can affect one type of blood cell or several — symptoms, therefore, vary depending on the cell types affected.

Myeloproliferative neoplasms (MPNs)

MPNs are a group of rare blood cancers that affect your bone marrow. They cause your bone marrow to produce too many red blood cells, white blood cells or platelets. MPNs develop slowly and many people do not have any symptoms. Symptoms that can occur include blurry vision, frequent headaches and infections, ringing in your ears, tiredness, and unusual bruising and bleeding.

What causes blood cancer?

While the exact cause of blood cancer is still unknown, several factors are linked to it developing. These include:

• Ageing — blood cancer is more common in older people
• Infections — infections with certain parasites, bacteria and viruses can increase your risk for blood cancer
• Family history — you can inherit genetic abnormalities that increase your risk of developing blood cancer
• Weak immune system — if you have a weakened immune system (eg if you have HIV) you are more likely to develop blood cancer

How are blood cancers treated?

There are different treatments for blood cancer depending on your general health, whether the cancer has spread, and the type and stage of blood cancer. Treatment options include:

Chemotherapy

This involves taking anti-cancer drugs in cycles to destroy the cancer cells. Treatment can take several months as you need to rest between each cycle to allow your body time to recover. You may have chemotherapy treatment on an inpatient or outpatient basis, depending on the type of blood cancer you have. Your doctor may inject chemotherapy drugs into your vein or give you tablets to take orally. The drugs will enter your blood and reach the cancer cells in your body.  

Immunotherapy

Also known as biotherapy, immunotherapy boosts your body’s own immune system to destroy the cancer cells or prevent them from multiplying. Immunotherapy can be active ie stimulate your immune system to specifically target the cancer cells, or passive ie boost the overall capability of your immune system.

Stem cell (bone marrow) transplant

This involves replacing your stem cells with healthy stem cells collected from a donor’s bone marrow or blood. There are two types of stem cell transplants: 

• Allogeneic transplantation — when you receive stem cells collected from an unrelated or related donor with a close genetic match
• Autologous transplantation — when your stem cells are collected before you receive a high dose of chemotherapy, which kills your cancer cells but as a side effect also kills your bone marrow stem cells; after your high-dose chemotherapy, your collected stem cells are reintroduced to your body so they can start producing healthy blood cells again

Is there a way to reduce your risk?

You can’t reduce your risk of developing blood cancer to zero but avoiding or reducing your exposure to carcinogens will help. Carcinogens are cancer-causing substances and include the following:

Benzene

Benzene is found in car exhaust fumes, detergents, some cleaning products, plastics, resins, solvents, paints, wood stains and varnishes. When shopping for household products, check the labelling for carcinogens, such as benzene, and buy products that are carcinogen-free. If you work in an industry that uses benzene, make sure you ask your employer to provide safety data sheets outlining the products you will be handling as well as appropriate protective clothing and equipment.

Formaldehyde

Formaldehyde is present in embalming fluid and is used in laboratories. It’s also found in permanent press clothing, wallpaper, upholstery, air fresheners and pressed wood products. Exterior-grade pressed wood products release less formaldehyde.

Certain pesticides

Certain garden and home pesticides, insecticides, and weed killers are linked to an increased risk of leukaemia in children. Try to avoid exposure to these, as well as flea treatments for pets.

Radon

Radon is a breakdown product of uranium that can be found in soil and rocks. You can check your local radon levels on Public Health England’s UK radon map. However, it is important to note that outdoor radon levels are usually low and not a danger to your health. Most radon-related cancers are caused by the combination of indoor radon levels and smoking.