Small lymphocytic lymphoma (SLL)
This information is about a type of non-Hodgkin lymphoma (NHL) called small lymphocytic lymphoma. It should ideally be read with our information about chronic lymphocytic leukaemia (CLL), which is essentially the same condition and is treated in the same way.
Sometimes small lymphocytic leukaemia is called CLL/SLL.
We hope this information answers your questions. If you have any further questions, you can ask your doctor or nurse at the hospital where you are having treatment.
SLL is a cancer of the lymphatic system. The lymphatic system is part of the body’s immune system and helps us fight infection. It's made up of organs such as the bone marrow, thymus, spleen, and the lymph nodes (or lymph glands). Lymph nodes are connected by a network of tiny lymphatic vessels that contain lymph fluid. There is also lymphatic tissue in other organs, such as the skin, lungs and stomach.
There are lymph nodes all over the body. As lymph fluid flows through the lymph nodes, the nodes collect and filter out anything harmful or anything that the body doesn't need. This includes bacteria, viruses, damaged cells and cancer cells.
Lymph fluid contains cells called lymphocytes. These are a type of white blood cell that help the body fight infection and disease.
Lymphocytes start to grow in the bone marrow, where blood cells are made. The two main types of lymphocyte are B-cells and T-cells. B-cells mature in the bone marrow, while T-cells mature in the thymus gland behind the breast bone. When they're mature, both B-cells and T-cells help fight infections.
Small lymphocytic lymphoma (SLL)
Back to top
SLL is a cancer of the B-cells. It is rare in people under 50 and more common in men than in women.
It is sometimes described as an indolent lymphoma and usually develops very slowly. In SLL abnormal B-cells build up in lymph nodes making them swell (enlarge). Abnormal B-cells may also build up in other parts of the body such as the bone marrow and spleen. If the bone marrow is affected it may not be able to make enough normal blood cells. This can lead to low levels of red blood cells in the blood (anaemia) and/or low levels of platelets (cells that help the blood to clot).
SLL is essentially the same condition as a type of leukaemia called chronic lymphocytic leukaemia (CLL). The only difference is that in SLL, at diagnosis the abnormal B-cells are in lymph nodes but not in the blood. Whereas in CLL, at diagnosis there are abnormal B-cells in the blood.
It’s not uncommon for a person to be diagnosed with SLL but for doctors to start calling their condition CLL if the number of white blood cells in their blood (white cell count) rises. This is nothing to be alarmed about and doesn’t mean the disease has changed or ‘transformed’ in any way.
The causes of small lymphocytic lymphoma are unknown. Like all cancers, it's not infectious and cannot be passed on to other people.
Signs and symptoms of SLL
Back to top
The first sign is often a painless swelling in the neck, armpit or groin, caused by enlarged lymph nodes. Sometimes lymph nodes in more than one area are affected. Other symptoms may include loss of appetite and tiredness (fatigue).
Some people have night sweats, an unexplained high temperature (fever) and weight loss. These are known as B symptoms.
A diagnosis is made by removing an enlarged lymph node (a biopsy) and examining the cells under a microscope. It is a very small operation and may be done under local or general anaesthetic. Biopsies may also be taken from other areas of the body.
Additional tests - including blood tests, x-rays, scans and bone marrow samples - may be used to find out how far SLL has spread in the body. Doctors use this information to decide which treatment is most appropriate for you.
You can read more about these tests in our information about tests for non-Hodgkin lymphoma.
Staging and grading of SLL
Back to top
Doctors use staging to assess the extent of SLL. This helps them to know when treatment is needed and which treatment is appropriate for each person.
There are different staging systems that can be used for SLL. The following staging system is based on how many groups of lymph nodes are affected, where they are in the body, and whether other organs such as the bone marrow or liver are involved.
One group of lymph nodes is affected, with the group being only in one area of the body, such as in the armpit, on one side of the neck or in the groin.
Two or more groups of lymph nodes are affected and they are all either above or below the diaphragm (the sheet of muscle under the lungs that separates the chest from the abdomen.)
The lymphoma is in lymph nodes both above and below the diaphragm.
The lymphoma has spread beyond the lymph nodes to other organs, such as the bones, liver or lungs.
As well as giving each stage a number, doctors also use either the letter A or B to show whether or not you have specific symptoms. If you have night sweats, fevers or weight loss, the letter B will be added next to the stage. If you don't have these symptoms, the letter A is added.
Another staging system that may be used is called the Binet system. It looks at how many areas of lymph nodes are enlarged and at the number of white cells, red cells and platelets in the blood.
There are less than three areas of enlarged lymph nodes.
Three or more areas of enlarged lymph nodes.
There is a reduced number of red cells, platelets or both.
There is more information about the Binet staging systems in our booklet Understanding chronic lymphocytic leukaemia.
If SLL is not causing symptoms, you may not need treatment immediately. Early treatment at this stage doesn’t increase a person’s life span and can cause side effects.
You will be seen regularly by your cancer specialist or GP, and treatment will be advised if you develop symptoms. It may be some time before this happens, and some people may never need any treatment.
After treatment, many people have a period of time with no signs of active disease, which is known as remission. If the lymphoma comes back, it can be treated again. This can give another period of remission and the lymphoma can often be controlled in this way for many years.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. It is an important treatment for small lymphocytic leukaemia and can often get the lymphoma into remission.
Chemotherapy is often given in combination with a drug called rituximab (Mabthera®), which is a monoclonal antibody that targets B-cells.
Chemotherapy can be given as tablets or into a vein (intravenously). You may be given just one type of chemotherapy drug or you may be given two or more drugs together (combination chemotherapy).
Chemotherapy treatments for small lymphocytic lymphoma include:
Cyclophosphamide and fludarabine can be given on their own or in combination (as FC). They can be given as tablets or as an injection into a vein. Sometimes the monoclonal antibody rituximab is given with fludarabine and cyclophosphamide. This is called FCR chemotherapy.
Bendamustine is sometimes used. It’s given as a drip into a vein (intravenously).
Another commonly used treatment for small lymphocytic lymphoma is a chemotherapy drug called chlorambucil. It comes as tablets and is usually given on its own.
Monoclonal antibody therapy
Monoclonal antibodies are drugs that recognise, target and stick to particular proteins on the surface of cancer cells, and can stimulate the body’s immune system to destroy these cells.
Rituximab is a monoclonal antibody used to treat small lymphocytic lymphoma. It's given as a drip into a vein (intravenous infusion). It is usually given with fludarabine and cyclophosphamide (as FCR).
Alemtuzumab is another monoclonal antibody that is sometimes used. It can be given as a drip into a vein (intravenous infusion) or as an injection under the skin (subcutaneous injection).
Steroids are drugs that are often given with chemotherapy to help treat lymphomas. They also help you feel better and can reduce feelings of sickness (nausea).
Stem cell treatment (transplants)
Some people with lymphoma may have treatments using their own stem cells or stem cells from a donor. Stem cells are early blood cells that develop into all the other types of blood cell. This treatment is not suitable for everyone and is not done routinely. Doctors take into account a person's general health and fitness before recommending them.
Some people have some of their own stem cells collected and stored. This allows them to have higher doses of chemotherapy to destroy the lymphoma cells. After the chemotherapy, their stem cells are returned by a drip (like a blood transfusion) to help their blood cells recover from the effects of chemotherapy. This is called high-dose treatment with stem cell support.
Some people may have treatment using stem cells from another person (a donor). This is called a donor (allogeneic) stem cell transplant.
Radiotherapy is the use of high-energy rays to destroy cancer cells, while causing as little harm as possible to healthy cells.
It may be used as a first treatment if the lymphoma cells are contained in one or two groups of lymph nodes in the same part of the body (stage 1). In some people, this may cure the SLL.
Radiotherapy can also be used to treat lymphoma that has come back in one area of lymph nodes.
Research into treatments for SLL is ongoing. Cancer specialists use clinical trials to assess new treatments. Before any trial is allowed to take place, an ethics committee must have approved it and agreed that the trial is in the interest of the patients.
You may be asked to take part in a clinical trial. Your doctor will discuss the treatment with you so that you have a full understanding of the trial and what it involves. You may decide not to take part, or to withdraw from a trial at any stage. You will still receive the best standard treatment available.
You may have many different emotions including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and are part of the process many people go through in trying to come to terms with their condition.
Everyone has their own way of coping with difficult situations. Some people find it helpful to talk to family or friends, while others prefer to seek help from people outside their situation. Some people prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is there if you need it. Our cancer support specialists can give you information about counselling in your area.
Other useful organisations
Back to top
The Lymphoma Association
The Lymphoma Association gives emotional support, advice and information on all aspects non-Hodgkin lymphoma. Has a national network of people with lymphoma and local groups.
Leukaemia CARE is a national group promoting the welfare of people with leukaemia and related blood disorders, including non-Hodgkin lymphoma. Has regional support groups in many counties.
This section has been compiled using information from a number of reliable sources, including:
Lee, et al. Wintrobe’s Clinical Haematology. 12th edition. 2009. Lippincott, Williams and Wilkins.
Marcus, et al. Lymphoma - Pathology, Diagnosis and Treatment. 2007. Cambridge University Press.
Thank you to Professor Rajnish Gupta, Consultant Medical Oncologist, and all of the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network.