What is non-Hodgkin lymphoma?

Non-Hodgkin lymphoma (NHL) is a type of blood cancer. It affects white blood cells called lymphocytes. It is also called a cancer of the lymphatic system. This is because it starts in lymph nodes Open a glossary item or other parts of the lymphatic system Open a glossary item.

The lymphatic system is a system of thin tubes and lymph nodes that run throughout the body. Lymph nodes are bean shaped glands. The thin tubes are called lymph vessels or lymphatic vessels. Tissue fluid called lymph circulates around the body in these vessels. And it flows through the lymph nodes.

The lymphatic system is an important part of our immune system. It plays a role in fighting bacteria and other infections. And it tries to destroy old or abnormal cells, such as cancer cells.

The diagram shows the lymph vessels, lymph nodes and other organs. These make up the lymphatic system.

Diagram of the lymphatic system

What is the difference between Hodgkin lymphoma and non-Hodgkin lymphoma?

There are 2 main types of lymphoma. They are called Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL).

Hodgkin lymphoma was named after the doctor who first recognised it. It used to be called Hodgkin's disease.

Hodgkin lymphoma has a particular appearance under the microscope. It contains cells called Reed-Sternberg cells. NHL looks different under the microscope and does not contain Reed-Sternberg cells.

Doctors need to tell the difference between Hodgkin lymphoma and NHL. They are two different diseases and the treatment for them is not the same. 

There are more than 60 different types of NHL. They can behave in very different ways. Your doctor or specialist nurse will tell you about the type you have.

This video explains what lymphoma is and how it starts. And the difference between Hodgkin lymphoma and non-Hodgkin lymphoma. The video lasts just over 3 minutes. 

How does non-Hodgkin lymphoma develop and affect you?

You develop lymphoma when white blood cells (lymphocytes Open a glossary item) divide abnormally and grow out of control.

Usually, we have just the right number of each type of cell. This is because cells produce signals to control how much and how often the cells divide. But sometimes cell division can get out of control. 

Normal white blood cells have resting time when they aren't dividing and making new cells. But if you have lymphoma, some of your white blood cells don't have any resting time. They divide continuously, so you produce too many. And the cells don't naturally die off as white blood cells normally do.

These cells start to divide before they are fully mature. So they can't fight infection as normal white blood cells do.

The abnormal white blood cells start to collect in the lymph nodes. Or they collect in other places such as the bone marrow or spleen. They can then grow into tumours and begin to cause problems in the lymphatic system, or in the organ where they are growing. For example, if a lymphoma starts in the thyroid gland it can affect the normal production of thyroid hormones.

Where does non-Hodgkin lymphoma start?

You can get NHL just about anywhere in your body. This is because the lymphatic system runs through your whole body. It most often starts in the lymph nodes and can affect several groups of lymph nodes around your body.

You can also find lymphoma in other body organs outside the lymphatic system. For example, the stomach or bones. 

Lymphoma that starts outside the lymphatic system

NHL can begin to develop outside the lymph nodes. This is called primary extranodal lymphoma. 

It can begin in almost any part of the body. The diagram below gives some examples of where lymphoma can start or spread to in the body.

Diagram showing where lymphoma can spread to in the body

Other cancers that have spread to the lymph nodes

Most types of cancer can spread to the lymph nodes. But they are not lymphoma. Lymphoma is cancer that starts in the lymph nodes. 

For example, if breast cancer spreads to the lymph nodes in the armpits it does not become lymphoma. The cancer cells that have spread to the lymph nodes are still breast cancer cells. So they are treated as breast cancer.

If your cancer has spread to the lymph glands (and is not lymphoma), you should look for information about that type of cancer.

Types of non-Hodgkin lymphoma

There are many different types of NHL. These types can be grouped (classified) in several different ways. Doctors look at different factors to group non-Hodgkin lymphoma (NHL) and find out your type.

B cell and T cell

NHL begins in a type of white blood cell called a lymphocyte. There are two types of lymphocytes. These are B cells and T cells. So you can develop a B cell lymphoma or a T cell lymphoma. There are then different types of B cell and T cell lymphomas.

High grade and low grade

Lymphomas are often grouped together as either high grade or low grade. The grade refers to how quickly they are likely to grow and spread.

The 2 groups are low grade (slow growing) and high grade (grow more quickly). The different grades of NHL are treated in slightly different ways.

NHL in children

The treatment for NHL in children is slightly different to NHL in adults. So while some of the information here is useful, you do need to be careful. We have separate information about NHL in children. 

How common is non-Hodgkin lymphoma?

Around 14,200 people are diagnosed with NHL each year in the UK. This makes it the 6th most common type of cancer in adults. 4 out of every 100 cancers diagnosed (4%) are NHL.

Who gets non-Hodgkin lymphoma?

It is more common in older people. Around 35 out of 100 (around 35%) of people diagnosed with NHL are aged 75 and over.

  • Cancer Incidence from Cancer Intelligence Statistical Information Team at Cancer Research UK  (2016 - 2018 UK average) 
    Accessed February 2024

  • The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms
    R Allagio and others
    Leukemia. 2022. Volume 36, Issue 7, Pages 1720-1748

  • Non-Hodgkin lymphoma
    James O Armitage and others.
    The Lancet 2017. Volume 390, Issue 10091, Pages 298–310

  • Cancer: Principles and Practice of Oncology (12th edition)
    VT DeVita, TS Lawrence, SA Rosenberg
    Wolters Kluwer, 2023

  • Hoffbrand's Essential Haematology (8th edition)
    A Victor and David P Steensma
    Wiley, 2019

Last reviewed: 
14 Feb 2024
Next review due: 
14 Feb 2027

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