Non-Hodgkin lymphoma (NHL) is a form of cancer of the lymphatic system.
The lymphatic system is part of your immune system and is a network of vessels and glands spread throughout your body. Clear fluid called lymph, flows through the lymphatic vessels and contains infection-fighting white blood cells known as lymphocytes. These lymphocytes originate in the bone marrow and circulate through the lymphatic system and into the blood stream.
In NHL, a lymphocyte starts to multiply in an uncontrolled way and these begin to collect together causing lumps or tumours. These lumps are most often located in lymph glands within the lymphatic system.
The most common symptom of NHL is a painless swelling in a lymph gland, usually in the neck, armpit or groin. Other symptoms of NHL may include drenching night sweats, unexplained loss of weight or fevers. Other symptoms can include; itch, fatigue or is dependent on where the lump or lymphoma has spread e.g. if the lump is in your chest it may produce a cough or if present in your abdomen may produce distension or abdominal pain.
As NHL originates from a lymphocyte which normally circulates around the body we do expect to find NHL in more than one place and it can possibly arise in any part of the body.
NHL accounts for 80% of all lymphomas diagnosed. In the UK, more than 12,000 cases are diagnosed each year.
NHL can occur at any age, but your chances of developing the condition increase as you get older, with most cases diagnosed in people over 65. Slightly more men than women are affected.
The exact cause of NHL is unknown.
Your risk of developing the condition is slightly increased if you have a medical condition that weakens your immune system, you take immunosuppressant medication, or you have previously been exposed to a common virus called the Epstein-Barr virus, which causes glandular fever.
You also have a small increased risk of developing NHL if a first-degree relative (parent, sibling or child) has had the condition.
There is also a small risk of developing NHL if you have had a previous diagnosis of Hodgkin lymphoma or other cancer which has been treated with chemotherapy or radiotherapy.