About non-Hodgkin lymphoma

Non-Hodgkin lymphoma is a blood cancer that begins in the white blood cells called lymphocytes. It used to be called non-Hodgkin’s disease. It is one of the two main groups of lymphoma. The other group is Hodgkin lymphoma.

Learn more about:

• Overview
• What is blood cancer?
• The lymphatic system
• The role of blood cells
• Common types of non-Hodgkin lymphoma
• Who gets non-Hodgkin lymphoma?
• What causes non-Hodgkin lymphoma?

Overview

Most commonly, non-Hodgkin lymphoma starts in a lymph node at one or more places in the body. It can spread through the lymphatic system from one group of lymph nodes to another. It can also spread to other lymph tissue, particularly in the bone marrow and spleen, or to lymph nodes in the liver.

Sometimes, non-Hodgkin lymphoma starts in or spreads to tissue in an organ outside the lymphatic system, such as the stomach, bone, skin, brain and spinal cord (central nervous system). This is known as extranodal disease.

What is blood cancer?

Cancer is a disease of the cells. Cells are the body’s basic building blocks – they make up tissues and organs. The body constantly makes new cells to help us grow, replace worn-out tissue and heal injuries.

Normally, cells multiply and die in an orderly way, so that each new cell replaces one lost. Cancer develops when cells become abnormal and keep growing. These abnormal cells may turn into cancer.

When a cancer begins in abnormal blood cells, it is known as a blood cancer. The three main groups of blood cancers are lymphoma, leukaemia and myeloma.

How lymphoma starts

Lymphoma is cancer of the body’s lymphatic system. In lymphoma, abnormal white blood cells called lymphocytes grow and multiply uncontrollably, and can form a lump (tumour), usually in a lymph node.

If abnormal lymphocytes continue to build up, they can spread through the lymph vessels to form a tumour in another part of the lymphatic system or, occasionally, in an organ outside the lymphatic system, such as the liver or lung.

Sometimes other types of cancer spread to the lymph nodes. This is not lymphoma. For example, breast cancer that has spread to the lymph nodes is still called breast cancer.

How lymphoma spreads

The lymphatic system

Non-Hodgkin lymphoma is a cancer of the lymphatic system. The lymphatic system is part of the immune system, which protects the body against disease and infection. The lymphatic system is made up of a network of vessels, tissues and organs:

Lymph vessels – These thin tubes are found throughout the body and in organs such as the spleen, liver, thymus gland and bone marrow. Lymph vessels carry lymph fluid around the body.

Lymph fluid – This clear fluid travels to and from the tissues in the body, carrying nutrients and taking away bacteria, viruses, abnormal cells and cell debris.

Lymph nodes – Also called lymph glands, these small, bean-shaped structures are made up of lymph tissue. There are about 600 lymph nodes all over the body. There are groups in the neck, underarms, chest, abdomen (belly) and groin. The lymph nodes filter lymph fluid before emptying most of the fluid into the bloodstream.

Parts of the lymphatic system

Other lymph tissue

As well as lymph nodes, lymph tissue is found in other parts of the body:

• bone marrow – produces blood cells
• thymus – a gland that helps produce a type of white blood cell known as T-cells
• spleen – stores white blood cells, filters waste products from the blood, and destroys old blood cells, abnormal cells and bacteria
• tonsils – trap inhaled or ingested germs
• digestive system – stores immune cells.

The role of blood cells

Bone marrow is the soft, spongy material inside bones. It makes stem cells, which are unspecialised blood cells that usually grow into one of three main types of blood cells: red blood cells, white blood cells and platelets. Each type of blood cell has a specific job to do.

White blood cells are part of the immune system and help fight infections. There are different types of white blood cells and they have different roles. The lymph nodes, lymph tissue and lymph fluid all contain the white blood cells known as lymphocytes.

Types of lymphocytes include:

• B-cells – make antibodies to fight infection
• T-cells – attack invaders (antigens) by killing them directly or by helping B-cells make antibodies
• natural killer (NK)-cells – rarer lymphocytes that specialise in killing cancer cells.

Diseases such as lymphoma or treatments such as chemotherapy can lower the number of blood cells in the body. This can cause:

• a low level of white blood cells (neutropenia), which makes you more likely to get infections
• a low level of red blood cells (anaemia), which may make you look pale and feel tired, breathless and dizzy
• a low level of platelets (thrombocytopenia), which means you bruise or bleed easily.

For more information about all types of blood cancers and the role of blood cells, visit the Leukaemia Foundation.

Types of blood cells

Common types of non-Hodgkin lymphoma

There are many different types of non-Hodgkin lymphoma, based on whether the lymphocyte affected is a B-cell, T-cell or NK-cell. It is also classified by how fast the lymphoma is growing such as slow-growing or fast-growing. Knowing the type of non-Hodgkin lymphoma you have will help your doctors plan your treatment.

Types of B-cell lymphomas

Around 85% of all non-Hodgkin lymphomas are B-cell lymphomas. The most common types of B-cell lymphomas are diffuse large B-cell and follicular lymphoma.

Types of T-cell lymphomas

Around 15% of all non-Hodgkin lymphomas are T-cell lymphomas. The most common type of T-cell lymphoma is angioimmunoblastic, followed by anaplastic large cell lymphoma.

Who gets non-Hodgkin lymphoma?

Each year in Australia, about 6400 people are diagnosed with non-Hodgkin lymphoma. It is more common in men than women. Most cases occur in adults aged 60 and older. Some types are more common in young adults and children. Non-Hodgkin lymphoma is the sixth most common cancer diagnosed in Australia.

What causes non-Hodgkin lymphoma?

The causes of non-Hodgkin lymphoma are largely unknown, but the risk factors include:

Weakened immune system – The risk of developing non-Hodgkin lymphoma is higher if your immune system has been weakened. This can happen if you have an autoimmune disease, such as rheumatoid arthritis or coeliac disease, or if you need to take medicines that suppress the immune system after an organ transplant.

Certain viruses – Some viruses can slightly increase the risk of developing non-Hodgkin lymphoma:

• Helicobacter pylori may increase risk of some types of lymphoma
• HTLV-1 (human T-cell lymphotropic virus 1) may increase the risk of some types of lymphoma
• hepatitis C
• Epstein-Barr virus
• HHV-8 (human herpesvirus 8).

Family history – Having a parent, brother or sister who has had non-Hodgkin lymphoma slightly increases a person’s risk of developing it. However, this family link is rare.

Breast implant associated anaplastic large cell lymphoma (BIA-ALCL) – Having a breast implant is linked with a rare type of lymphoma called breast implant associated anaplastic large cell lymphoma (BIA–ALCL). This includes having an implant for a breast enlargement or to reconstruct the breast after surgery for breast cancer.

Although it develops in the breast, BIA–ALCL is a type of lymphoma, not a type of breast cancer. The risk of developing an anaplastic large cell lymphoma following an implant is small. This can happen many years after having the implant. BIA–ALCL is more common with textured implants.

The Therapeutic Goods Administration (TGA) recommends that women who have implants monitor their breasts for any changes, such as sudden fluid collection. Every year, ask your surgeon or GP to check the implants. You can read more about BIA–ALCL on the TGA’s website (visit tga.gov.au and search “BIA–ALCL for consumers”). The TGA also has an online breast implant hub, where information and support related to breast implants and their safety are updated as new information becomes available. If you are concerned, talk to your surgeon.

Most people with known risk factors don’t develop non-Hodgkin lymphoma, and some people who do get it have no known risk factors. Non-Hodgkin lymphoma is not contagious.

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