Lymphoma is a cancer of the lymphatic system. It develops when blood cells called lymphocytes become abnormal. Normal lymphocytes fight infection. They are part of the lymphatic system. This is the system that helps protect your body from infection and disease. It is made up of fine tubes connected to groups of small lymph nodes throughout the body. 

How lymphoma develops and the treatment you may need depends on the type of lymphoma. The 2 main types are:

• Hodgkin lymphoma
• non-Hodgkin lymphoma (NHL).

There are also sub-types of lymphoma within these 2 main types. A doctor can only find out the type of lymphoma you have by collecting some lymphoma cells and testing them in a laboratory. If the sample contains a type of cell called Reed-Sternberg cells, the lymphoma is usually Hodgkin lymphoma. If there are no Reed-Sternberg cells, it is non-Hodgkin lymphoma. The most common symptom of lymphoma is a painless swelling in the neck, armpit or groin.

Non-Hodgkin lymphoma (NHL) is the 6th most common cancer in the UK. Around 14,000 people are diagnosed with it each year. It can affect people at any age but is more common as people get older. Most people diagnosed with NHL are aged over 55.

Around 2,100 people are diagnosed with Hodgkin lymphoma in the UK each year. Hodgkin lymphoma can happen at any age. It is one of the most common cancers to affect people in their teens and early 20s.