Non-Hodgkin's lymphoma is a cancer which affects lymphocyte cells in the lymphatic system. The various types of non-Hodgkin's lymphoma are divided into high-grade (fast growing) and low-grade (slow growing). There are various treatments but chemotherapy is usually given. Many people with non-Hodgkin's lymphoma are cured.
What is lymphoma?
A lymphoma is a cancer of cells in the lymphatic system. Lymphomas are divided into two types - Hodgkin's lymphoma and non-Hodgkin's lymphoma. There are different types of non-Hodgkin's lymphoma. It is important to know exactly what type you have. This is because the treatments and outlook (prognosis) can vary for different types of lymphoma.
The rest of this leaflet is only about non-Hodgkin's lymphomas. Around 4 out of 5 cases of lymphoma are non-Hodgkins lymphoma.
What is the lymphatic system?
The lymphatic system consists of lymph nodes (lymph glands), a network of thin lymphatic channels (similar to thin blood vessels), and organs such as the spleen and thymus.
Small lymph nodes occur throughout the body. Lymph nodes that are near each other often form into groups or chains - for example, in the sides of the neck (cervical lymph nodes), the armpits (axillary lymph nodes), and in the groin (inguinal lymph nodes). The diagrams above show the main groups of lymph glands, but they occur in many places in the body.
Lymph nodes are joined together by a network of lymphatic channels. Lymph mainly consists of a fluid that forms between the cells of the body. This contains nutrients and waste products which go into and out of cells. The watery lymph fluid travels in the channels, through various lymph nodes and eventually drains into the bloodstream.
The lymphatic system is also a major part of the immune system. Lymph and lymph nodes contain white blood cells called lymphocytes and antibodies which defend the body against infection. The lymphocytes are made in the bone marrow. When they are mature they are released into the bloodstream and migrate into the lymphatic system. There are three types of mature lymphocytes:
- B lymphocytes which make antibodies that attack infecting bacteria, viruses, etc.
- T lymphocytes (which finish off their maturing in the thymus gland) have various functions, including helping the B lymphocytes to make antibodies.
- Natural killer lymphocytes which also help to protect against infection.
What is cancer?
Cancer is a disease of the cells in the body. The body is made up from millions of tiny cells. There are many different types of cell in the body, and there are many different types of cancer which arise from each different type of cell. What all types of cancer have in common is that the cancer cells are abnormal and do not respond to normal control mechanisms. Large numbers of cancer cells build up either because they multiply out of control, or they live much longer than normal cells would do, or both. Lymphoma is one type of cancer.
A malignant tumour is a growth of tissue made up from cancer cells which continue to multiply. Malignant tumours invade into nearby tissues and organs, which can cause damage.
Malignant tumours may also spread to other parts of the body. This happens if some cells break off from the first (primary) tumour and are carried in the bloodstream or lymph channels to other parts of the body. These small groups of cells may then multiply to form secondary tumours (metastases) in one or more parts of the body. These secondary tumours may then grow, invade and damage nearby tissues, and spread again.
Some cancers are more serious than others, some are more easily treated than others (particularly if diagnosed at an early stage) and some have a better outlook than others.
So, cancer is not just one condition. In each case it is important to know exactly what type of cancer has developed, how large it has become, and whether it has spread. This will enable you to get reliable information on treatment options and outlook.
See separate leaflet called Cancer - What are Cancer and Tumours? for further details about cancer in general.
What causes a non-Hodgkin's lymphoma and how does it develop?
The cause is not known. If your immune system does not work well (for example, if you have AIDS) your risk of developing a non-Hodgkin's lymphoma is increased. However, this only accounts for a small number of cases and the cause is unknown for most people. It is not an inherited condition and does not run in families.
The cancer seems to start from one abnormal cell. In the case of non-Hodgkin's lymphoma, the cancer develops from a lymphocyte cell which becomes abnormal. The exact reason why the cell becomes cancerous is unclear. It is thought that something damages or alters certain genes in the cell. This makes the cell abnormal. If the abnormal cell survives, it may multiply and produce many abnormal cells.
See separate leaflet called What Causes Cancer? for more details.
The cancerous lymphocytes tend to collect in lymph nodes. The lymph nodes become bigger and form cancerous tumours. Some abnormal cells may travel to other parts of the lymphatic system such as the spleen. So you may develop lots of large cancerous lymph nodes and an enlarged spleen.
Cancerous lymphocytes can also form lymphoma tumours in places in the body outside of the lymphatic system. This is because lymphocytes can also travel in the bloodstream. Differing types of non-Hodgkin's lymphoma can cause tumours to develop in the lining of the stomach or, rarely, in the brain.
Who gets non-Hodgkin's lymphoma and how common is it?
Anyone can be affected. Most cases occur in people over the age of 60. About 10,000 people in the UK develop a non-Hodgkin's lymphoma each year. It is the seventh most common type of cancer in the UK. Men are more commonly affected than women.
What are the symptoms of non-Hodgkin's lymphoma?
Swollen lymph nodes
The most common early symptom is to develop one or more swollen lymph nodes in one area of the body - most commonly the side of the neck, an armpit or the groin. The swollen lymph nodes tend to be painless and gradually get bigger. They can sometimes be painful though. If the affected lymph nodes are in the chest or abdomen, you may not be aware of them in the early stages of the disease.
(Note: the most common cause of swollen lymph nodes is infection. For example, it is very common to develop swollen nodes in the neck during tonsillitis. Lymphoma is an uncommon cause of swollen lymph nodes. However, a lymphoma may be suspected if lymph nodes remain swollen, or if there is no infection to cause the swelling.)
Other general symptoms may develop. For example: sweats (especially at night), fevers, weight loss, tiredness, being off food, anaemia, itch all over the body.
Various other symptoms may develop if the lymphoma occurs outside the lymphatic system. For example, stomach pain if the lymphoma develops in the stomach.
As a non-Hodgkin's lymphoma develops you may feel generally unwell. If the lymphoma tumours become large and press on nearby parts of the body, various other symptoms can develop. For example, you may develop cough or breathing problems if the tumour is in the chest.
How is non-Hodgkin's lymphoma diagnosed and assessed?
To confirm the diagnosis
If your doctor suspects that you may have a lymphoma you will be referred to a specialist. A specialist will normally arrange a biopsy of one of the swollen nodes. A biopsy is when a small sample of tissue is removed from a part of the body. Sometimes an entire lymph node is removed. The sample is then viewed under a microscope to look for abnormal cells. The sample is also tested in other ways.
Grade of the lymphoma
The microscope allows abnormal cells to be seen. By looking at certain features of the cells, and by doing various other tests on the cells, the exact type of lymphoma can be diagnosed. Examples of types of non-Hodgkin's lymphomas include: diffuse large B-cell lymphoma, lymphoblastic lymphoma, follicular lymphoma, anaplastic large-cell lymphoma, lymphoplasmacytic lymphoma and mantle cell lymphoma - but there are various other types.
Although there are many types of non-Hodgkin's lymphoma, they are generally divided (graded) into two categories - high-grade and low-grade.
- High-grade (fast-growing). The cancerous cells tend to grow and multiply quite quickly and are more aggressive.
- Low-grade (slow-growing). The cancerous cells tend to grow and multiply quite slowly and are not so aggressive.
Assessing the extent and spread (staging)
If the biopsy confirms that you have a non-Hodgkin's lymphoma, then further tests are usually advised. For example, you may have a CT or MRI scan, blood tests, a bone marrow biopsy or other tests. (See separate leaflets which describe these tests in more detail.) This assessment is called staging. The aim of staging is to find out how much the lymphoma has grown locally, and whether it has spread to other lymph nodes or to other parts of the body. The staging system that is commonly used for non-Hodgkin's lymphomas is:
- Stage 1 - the lymphoma is confined to one group of lymph nodes only.
- Stage 2 - the lymphoma affects two or more groups of lymph nodes. However, they are all on the same side of the diaphragm. (The diaphragm is the large muscle that separates the chest from the abdomen and helps us to breathe. So, for stage 2, all the affected nodes will either be above or below the diaphragm.)
- Stage 3 - the lymphoma affects nodes on both sides of the diaphragm.
- Stage 4 - the lymphoma affects parts of the body outside of the lymphatic system.
Each stage is also divided into A or B. A means that you do not have symptoms of night sweats, fevers or weight loss. B means that you do have one or more of these symptoms. So, for example, if you have stage 2B, it means that you have two or more groups of lymph nodes affected, but both are either above or below the diaphragm, and you also have one or more of night sweats, fevers or weight loss.
By finding out the type, grade and stage of the lymphoma it helps doctors to advise on the best treatment options. It also gives a reasonable indication of outlook.
What are the treatments for non-Hodgkin's lymphoma?
The treatment advised for each case depends on various factors such as the exact type and stage of the lymphoma. In particular, whether it is high or low-grade, your age, your general health, the size of the affected nodes, and which parts of the body are affected.
Treatments which may be considered include the following:
Chemotherapy is a treatment which uses anti-cancer medications to kill cancer cells, or to stop them from multiplying. High-grade non-Hodgkin's lymphomas are usually treated with chemotherapy medicines given straight into the vein (intravenous chemotherapy). A combination of medicines is usually used. The most common combination used is with the medicines: cyclophosphamide, doxorubicin, vincristine and prednisolone. (This combination is often called CHOP.)
For low-grade non-Hodgkin's lymphomas, when active treatment is advised then intravenous chemotherapy or chemotherapy tablets are the most commonly used treatments. (See separate leaflet called Chemotherapy for more details.)
This treatment is sometimes used in addition to chemotherapy. (For example, a product called rituximab is the commonly used monoclonal antibody.) Monoclonal antibodies are small proteins and are different to normal chemotherapy. They work by attaching to the abnormal lymphocytes, which helps to destroy them without harming other cells.
Radiotherapy is a treatment which uses high-energy beams of radiation which are focused on cancerous tissue. This kills cancer cells, or stops cancer cells from multiplying. It tends to be mainly used if you just have one or two affected lymph nodes. (See separate leaflet called Radiotherapy for more details.)
Stem cell transplant
A stem cell transplant (sometimes called a bone marrow transplant) is sometimes done. Stem cells are the immature cells that develop into mature blood cells (including lymphocytes) in the bone marrow. First high-dose chemotherapy (and sometimes radiotherapy) is given to kill all the abnormal lymphocytes. However, this also kills the stem cells that make normal blood cells. So, after the chemotherapy, you are given a transplant of stem cells which then make normal blood cells. The transplant will usually come from someone else, who has healthy cells.
See separate leaflet called Stem Cell Transplant for more details.
Surgery is not used very often. Occasionally, an operation may be done to remove an organ (such as the spleen) or part of an organ that is badly damaged by a lymphoma. Sometimes a large mass of tumour may be removed to de-bulk the tumour prior to chemotherapy.
Watch and wait
No treatment may be advised initially for low-grade non-Hodgkin's lymphomas. This approach is called watch and wait. This approach is mainly used if you feel generally well and have no symptoms from the lymphoma (apart from painless swollen nodes). Low-grade non-Hodgkin's lymphomas can grow very slowly and may not need any treatment for quite some time - often over a year.
Chemotherapy or other treatments may be delayed until the disease causes symptoms. Your specialist will want to review you regularly to check on the size of the lymph nodes, how fast they are growing and to check you over. They will advise on when treatment should be started.
You should have a full discussion with a specialist who knows your case. They will be able to give the pros and cons, likely success rate, possible side-effects, and other details about the possible treatment options for your type and stage of lymphoma.
You should also discuss with your specialist the aims of treatment. For example:
- Treatment may aim to cure the lymphoma. Some non-Hodgkin's lymphomas can be cured. In particular, most high-grade non-Hodgkin's lymphomas can be cured with treatment. Doctors tend to use the word remission rather than the word cured. Remission means there is no evidence of lymphoma following treatment. If you are in remission, you may be cured. However, in some cases, a lymphoma returns months or years later. This is why doctors are sometimes reluctant to use the word cured.
- Treatment may aim to control the lymphoma. If a cure is not realistic, it is often possible to limit the growth or spread of the lymphoma with treatment. This usually means that it progresses less rapidly. This may keep you free of symptoms for some time. Many low-grade non-Hodgkin's lymphomas cannot be cured but can be controlled, often for quite some time.
- Treatment may aim to ease symptoms. If a cure is not possible, treatments may be used to reduce the size of lymphoma tumours. This may ease symptoms such as pain. If a non-Hodgkin's lymphoma is advanced then you may require treatments such as painkillers or other treatments to help keep you free of pain or other symptoms.
What is the outlook?
The outlook depends on various factors which include the exact type, grade and stage of the lymphoma. Very generally:
Many people with a high-grade non-Hodgkin's lymphoma will be cured. Therefore, the usual aim of treatment for high-grade non-Hodgkin's lymphoma is to cure it. A cure is most likely in cases which are at an early stage, but there is still a good chance of a cure even with those in more advanced stages. Although a high-grade non-Hodgkin's lymphoma is fast-growing and aggressive, the cells tend to be more easily killed with chemotherapy than low-grade non-Hodgkin's lymphomas.
With slow-growing low-grade non-Hodgkin's lymphomas, chemotherapy is less likely to be curative than with high-grade non-Hodgkin's lymphomas. However, treatment may control the disease and keep you free of symptoms for months or years. Also, because they are slow-growing, often low-grade non-Hodgkin's lymphomas appear to be indolent and not really to progress very much for quite some time.
The treatment of cancers such as non-Hodgkin's lymphoma is a developing area of medicine. New treatments continue to be developed and the information on outlook above is very general. The specialist who knows your case can give more accurate information about your particular outlook, and how well your type and stage of non-Hodgkin's lymphoma are likely to respond to treatment.
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Further help & information
Dr Tim Kenny
Dr Hayley Willacy
Dr Colin Tidy