Lymphoma is a cancer that affects the lymphatic system, which is part of your immune system. The lymphatic system is made up of a network of tubes (lymph vessels) and glands (lymph nodes) throughout your body.

The lymphatic system collects and filters waste products from the body in a clear fluid called lymph. The lymph also contains white blood cells called lymphocytes, which fight infection.

Lymphoma occurs when the lymphocytes are damaged. This damage can make them cancerous, which is where they grow and multiply abnormally. When this happens, the abnormal lymphocytes lose their ability to fight off infections.

There are two main types of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. They are spread and treated differently.

The symptoms of Hodgkin and non-Hodgkin lymphoma are similar. The most common symptom is a painless swelling in one or more lymph nodes, usually in the neck, armpit or groin.

Both lymphoma types are diagnosed by biopsy, where a sample of the affected lymph tissue is tested.

Treatment for lymphoma is usually chemotherapy, radiotherapy or both. If you are having treatment for lymphoma, the choice of treatment depends on:

• the type of lymphoma (Hodgkin or non-Hodgkin)
• your age and general health
• your symptoms
• whether or not the disease has spread to other areas of the body
• what you want.

If you suspect you or some you know has lymphoma, it is important to see a doctor as soon as possible.