Hodgkin's lymphoma is a form of cancer that affects cells in the lymphatic system, called B lymphocytes. It can affect anyone of any age, but it most commonly affects young adults. With treatment, the outlook is very good. Most people with Hodgkin's lymphoma are completely cured. Treatment is usually with a course of chemotherapy, sometimes also with radiotherapy. A stem cell transplant is sometimes needed.
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 lymphomas (which are a varied group). Most lymphomas are non-Hodgkin's lymphoma. About 1 in 5 cases are Hodgkin's lymphoma. It is important to know exactly what type of lymphoma you have. This is because the treatments and outlook (prognosis) vary for different types of lymphoma.
The rest of this leaflet is only about Hodgkin's lymphoma (sometimes called Hodgkin's disease). The disease is named after the doctor who first described it in 1832.
See separate leaflet called Non-Hodgkin's Lymphoma.
What is the lymphatic system?
The lymphatic system consists of lymph nodes (often called 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 groins (inguinal lymph nodes). The diagrams above show the main groups of lymph nodes (lymph glands), but lymph nodes occur in many other 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 lymph 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 germs (bacteria, viruses, etc).
- T lymphocytes which 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 of millions of tiny cells. There are many different types of cell in the body. Different types of cancer can develop from different types of cell. What all types of cancer have in common is that the cancer cells are abnormal. 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.
A malignant tumour is a lump or 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), 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 What is Cancer? for further details about cancer in general.
What causes Hodgkin's lymphoma and how does it develop?
The cause is not known. If you have a poorly functioning immune system (for example, if you have AIDS) your risk of developing a Hodgkin's lymphoma is increased. However, this only accounts for a small number of cases. A previous infection with a virus called the Epstein-Barr virus (which causes glandular fever) may increase the risk slightly. However, many people have an infection with the Epstein-Barr virus, and only a few will develop Hodgkin's lymphoma.
What seems to happen is that a cancer (such as a lymphoma) starts from one abnormal cell. In the case of Hodgkin's lymphoma, the cancer develops from a B-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.
Hodgkin's lymphoma is not an inherited (genetic) condition and does not run in families. However, an identical twin of a person with Hodgkin's lymphoma has a slightly higher risk of developing Hodgkin's lymphoma.
The cancerous lymphocytes tend to collect in lymph glands (nodes). The lymph nodes then get bigger and form cancerous tumours. Some abnormal cells may travel to other parts of the lymphatic system. You may therefore develop lots of large cancerous lymph nodes, and an enlarged spleen.
Who gets Hodgkin's lymphoma and how common is it?
Anyone can be affected, including children. However, most cases occur between the ages of 20 and 25 years, or after the age of 70. It is one of the few cancers where there is a peak of incidence in young adults. It affects around 1,500 people in the UK each year. Men are more commonly affected than women.
What are the symptoms of Hodgkin's lymphoma?
Swollen lymph glands (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, the armpit or the groin. The swollen lymph nodes tend to be painless and gradually get bigger. A symptom which occurs in about 1 in 10 cases is pain in the affected lymph glands after drinking alcohol. If the affected lymph nodes are in the chest or tummy (abdomen), you will not be aware of them swelling 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 a bout of tonsillitis. Lymphoma is an uncommon cause of swollen lymph nodes. However, a lymphoma may be suspected if lymph nodes remain swollen for more than a couple of weeks or so, or if there is no infection to account for the swelling.
Various other general symptoms may develop - for example:
- Sweats (especially at night)
- High temperature (fever)
- Weight loss
- Being off food
- Itch all over the body
As a 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 a cough or breathing problems if the tumour enlarges in the lymph nodes inside the chest.
How is Hodgkin's lymphoma diagnosed and assessed?
To confirm the diagnosis (biopsy)
If your doctor suspects that you may have a Hodgkin's lymphoma you will be referred to a specialist. A specialist will normally arrange a biopsy of one of the swollen nodes. During a biopsy procedure a small sample of tissue is removed from a part of the body. The sample is then looked at under the microscope to look for abnormal cells. Usually an entire lymph gland (node) is removed to look at under the microscope.
In Hodgkin's lymphoma, a cell called the Reed-Sternberg cell is seen when the biopsy sample is examined under the microscope. (This cell is named after the two doctors who first described it. The Reed-Sternberg cell is a B lymphocyte that has become cancerous.) The presence of the Reed-Sternberg cell confirms the diagnosis, as it is only found in Hodgkin's lymphoma. Only about 1 in 1,000 of the cells in a Hodgkin's lymphoma are Reed-Sternberg cells. There are various other cells which make up the tumour. However, Reed-Sternberg cells are the characteristic cancerous cells found in this condition.
There are various subtypes of Hodgkin's lymphoma. The cells in the biopsy sample can be tested in various other ways to find out exactly which type it is. However, all types include the characteristic Reed-Sternberg cell, and the treatment and outlook are similar for all the types of Hodgkin's lymphoma.
Assessing the extent and spread (staging)
If the biopsy confirms that you have a Hodgkin's lymphoma, then further tests are usually advised. For example, you may have a CT scan, an MRI scan, a PET scan, blood tests, a bone marrow biopsy or other tests. (See separate leaflets which describe each of these tests in more detail.) This assessment is called 'staging'. The aim of staging is to find out how much the lymphoma has grown, and whether it has spread to other lymph nodes or to other parts of the body. The staging system that is commonly used for Hodgkin's lymphoma is:
- Stage I - the lymphoma affects one group of lymph nodes only.
- Stage II - 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 tummy (abdomen) and helps us to breathe. So, for stage II, all the affected nodes will either be above or below the diaphragm.)
- Stage III - the lymphoma affects nodes on both sides of the diaphragm.
- Stage IV - 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, high temperature (fever) or weight loss. B means that you do have one or more of these symptoms.
For an example, if you have Stage IIB, it means that you have two or more groups of lymph nodes affected; however, 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 stage of the lymphoma it helps doctors to advise on the best treatment options. See separate leaflet called Staging and Grading Cancer for more detail.
What are the treatments for Hodgkin's lymphoma?
Treatment for Hodgkin's lymphoma is usually with medicines that destroy the cancer cells (chemotherapy), with or without radiotherapy.
Chemotherapy is a treatment which uses anti-cancer medicines to kill cancer (lymphoma) cells, or to stop them from multiplying. Hodgkin's lymphomas are usually treated with chemotherapy medicines given straight into the vein (intravenous chemotherapy). The course of chemotherapy typically lasts several months. A combination of medicines is usually used. The exact combination of medicines used and the length of the course of chemotherapy depend on factors such as the stage and exact type of the disease.
See separate leaflet called Chemotherapy with Cytotoxic Medicines for more details.
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. Radiotherapy alone may be used for early-stage disease. It may also be used in combination with chemotherapy.
See separate leaflet called Radiotherapy for more details.
Stem cell transplant
A stem cell transplant (sometimes called a bone marrow transplant) is not a usual treatment, as chemotherapy and radiotherapy usually cure the disease. It tends to be used if the disease returns (relapses) after the usual treatment. Stem cells are the immature cells that develop into mature blood cells in the bone marrow. Lymphocytes are derived from blood stem cells.
Briefly, a stem cell transplant involves high-dose chemotherapy (and sometimes radiotherapy) 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.
See separate leaflet called Stem Cell Transplant for more details.
You should have a full discussion with a specialist who knows your case. They will be able to give you information on:
- The pros and cons.
- The likely success rate.
- Possible side-effects.
- Other details about the treatment options for your type and stage of Hodgkin's lymphoma.
What is the outlook (prognosis)?
The outlook is generally very good. It often responds very well to treatment and is one of the most curable forms of cancer. About 8 or 9 people out of 10 with the disease will have permanent remission. The cure rate tends to be highest in younger people. So, for example, virtually all young adults with early-stage disease can expect to be completely cured. Unlike other types of cancer, it is often possible to cure Hodgkin's lymphoma even if the initial treatments are not successful.
The treatment of lymphoma is a developing area of medicine. New treatments continue to be developed and the information on outlook above is very general. There are some newer medicines that have been introduced in the last few years that show promise to improve the outlook. The specialist who knows your case can give more accurate information about the outlook for your particular situation.
Further help & information
Dr Tim Kenny
Dr Colin Tidy
Dr John Cox