What is small lymphocytic lymphoma (SLL)?

Small lymphocytic lymphoma (SLL) is a slow-growing type of non-Hodgkin lymphoma (NHL). It is similar to and treated in the same way as chronic lymphocytic leukaemia (CLL).

It develops when B-cells (also called B-lymphocytes) become abnormal. B-cells are white blood cells that fight infection.

The abnormal B-cells (lymphoma cells) build up in lymph nodes.

Symptoms of small lymphocytic lymphoma (SLL)

Painless swelling in neck, armpit or groin

This is often the first sign of SLL. It is caused by lymphoma cells building up in the lymph nodes, which makes them bigger.

B symptoms

Some people also have:

  • drenching night sweats
  • high temperatures (fevers) with no obvious cause
  • unexplained weight loss

Doctors call this group of symptoms B symptoms.

Other symptoms

Other symptoms may include loss of appetite and tiredness (fatigue).

Sometimes lymphoma cells may build up in the bone marrow, where blood cells are made. This can cause:

  • anaemia - due to low number of red blood cells in your blood
  • bruising or bleeding easily - due to low number of blood-clotting cells (platelets) in your blood.

We have more information about the signs and symptoms of lymphoma.

Causes of small lymphocytic lymphoma (SLL)

The causes of SLL are not known. Like other cancers, it is not infectious and cannot be passed on to other people. It is more common as people get older. The most common age to be diagnosed with SLL is 65.

We have more information about causes and risk factors of non-Hodgkin lymphoma.

Diagnosis of small lymphocytic lymphoma (SLL)

The most important test for diagnosing lymphoma is a biopsy. A doctor or nurse will take a sample of tissue from the affected area. The most common place to take a biopsy from is an enlarged lymph node. This is called a lymph node biopsy. You may have all or a part of the lymph node removed. The tissue will be sent to a laboratory for testing.

Staging and grading of small lymphocytic lymphoma (SLL)

The results of your tests help your doctors find out how many areas of the body are affected by lymphoma and where these areas are. This is called staging.

Lymphomas are also grouped as either low-grade or high-grade. Low-grade lymphomas are usually slow growing and high-grade lymphomas grow more quickly. SLL is a low-grade lymphoma and usually develops slowly. Sometimes it can change (transform) to become a high-grade lymphoma.

We have more information about staging and grading of non-Hodgkin lymphoma.

Treatment for small lymphocytic lymphoma (SLL)

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor or cancer specialist or nurse will explain the different treatments and their side effects. They will also talk to you about things to consider when making treatment decisions.

SLL usually develops slowly. Some people may not need treatment for months or years. During this time they will have regular check-ups to monitor the lymphoma. This is called watch and wait.

Your treatment may depend on:

  • the stage of the lymphoma
  • whether you have symptoms that are causing problems.

Treatments for SLL may include the following:

  • Chemotherapy

    It is an important treatment for SLL and can often get the lymphoma into remission. Chemotherapy is usually given in combination with targeted therapies. The following drugs may be used to treat SLL:

    • FCR
    • Bendamustine - is given with rituximab, or sometimes given on its own.
    • Chlorambucil - is given with a targeted therapy, or sometimes given on its own.
  • Targeted therapy

    The most commonly used type of targeted therapy is a monoclonal antibody called rituximab. Other monoclonal antibody treatments for SLL include: 

    Another type of targeted therapy for SLL are called B-cell receptor inhibitors. They may be used to treat a particular type of SLL that does not respond well to chemotherapy. B-cell receptor inhibitors include:

    • ibrutinib (Imbruvica®)
    • idelalisib (Zydelig®).
  • Steroids

    Steroids are drugs that are often given with chemotherapy to treat lymphomas. They help make chemotherapy more effective.

  • Stem cell transplants

    Stem cell transplants are sometimes used to treat lymphoma that has come back after treatment. Stem cell transplants are intensive treatments, so they are not suitable for everyone. You may have a transplant using your own stem cells autologous stem cell transplant or cells from a donor allogeneic stem cell transplant.

  • Radiotherapy

    Radiotherapy uses high-energy rays to destroy cancer cells, while causing as little harm as possible to normal cells. It may be used as a first treatment if the abnormal B-cells are contained in 1 or 2 groups of lymph nodes in the same part of the body. 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. Your doctor may also suggest radiotherapy to treat an enlarged spleen.

You may have some treatments as part of a clinical trial.

For most people, the aim of treatment is to get rid of as much of the lymphoma as possible. If there are no signs of lymphoma after treatment, this is called a complete remission.

After treatment, many people have a period of time with no signs of active disease. This is called remission. If the lymphoma comes back, it may be treated again and can often be controlled for many years.

After small lymphocytic lymphoma treatment (SLL)

You have regular follow-up appointments after treatment. These appointments are a good opportunity for you to talk to your doctor or nurse about any concerns you have. Your doctor will want to know how you are feeling generally, and to check you are recovering from any side effects of treatment.

Late effects

Sometimes a side effect may continue or develop months or years after treatment. This is called a late effect.

We have more information about long-term and late effects of treatment for lymphoma.

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment.

Making small changes such as eating well and keeping active can improve your health and wellbeing and help your body recover.

Getting support

Everyone has their own way of dealing with illness and the different emotions they experience. You may find it helpful to talk things over with family and friends or your doctor or nurse.

Macmillan is also here to support you. If you would like to talk, you can:

The organisations below also offer information and support:

  • Blood Cancer UK

    Blood Cancer UK is a blood cancer research charity that provides information and support on any type of blood cancer.

  • Lymphoma Action

    Lymphoma Action gives emotional support, advice and information on all aspects of Hodgkin lymphoma and non-Hodgkin lymphoma. It has a national network of people with lymphoma, and local groups.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Professor Rajnish Gupta, Macmillan Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Reviewed: 31 January 2018
Reviewed: 31/01/2018
Next review: 31 January 2020
Next review: 31/01/2020