What is splenic marginal zone lymphoma?
Lymphoma is a type of cancer. It happens when growth of a lymphocyte (white blood cell) population goes out of control.
Marginal zone lymphomas develop from B lymphocytes (B cells) that are normally found in the ‘marginal zone’. This is at the edge of the area of lymphoid tissue and is where the B cells are found (lymphoid tissue is part of the immune system, such as the lymph nodes or spleen).
Splenic marginal zone lymphoma (splenic MZL) is a type of low-grade (slow-growing) non-Hodgkin lymphoma (NHL). It is a rare type of lymphoma – fewer than 2 in 100 cases of NHL are splenic MZL.
What is the spleen?
The spleen is an organ of your immune system. It is involved in fighting infection, filtering your blood and destroying old blood cells. You can’t normally feel your spleen, but an enlarged (swollen) spleen might feel like a lump at the top left of your abdomen (tummy).
Splenic MZL can affect people of any age but is most common in people in their 60s.
In most cases, it is not known what causes splenic MZL. This type of lymphoma is more common in people who have had certain infections, particularly hepatitis C virus, but also Epstein–Barr virus or malaria. People with autoimmune conditions that affect B cells, like Sjögren syndrome or systemic lupus erythematosus (SLE) also have an increased risk of developing splenic MZL.
The vast majority of people who have these conditions or viruses do not go on to develop lymphoma.
Splenic MZL usually causes enlargement of your spleen, which may become very big. This is called ‘splenomegaly’. It can cause abdominal (tummy) pain or discomfort.
Some people have no symptoms of splenic MZL. An enlarged spleen might be discovered if your doctor is examining your abdomen during a routine examination. Abnormal cells might be found in a blood test done for another reason.
Some people have symptoms caused by lymphoma in their bone marrow (the spongy tissue in the centre of bones where blood cells are made). These include:
- anaemia (a shortage of red blood cells), which can cause tiredness and shortness of breath
- thrombocytopenia (a shortage of platelets), which can cause you to bruise or bleed more easily than usual.
Some people experience generalised symptoms like weight loss, fevers and night sweats. These are known as ‘B symptoms’ and often occur together.
Splenic MZL can be difficult to diagnose. An enlarged spleen is not usually due to cancer. It is more commonly caused by infections and other conditions. NHS Choices have more information on problems of the spleen.
Splenic MZL can look similar to other types of lymphoma like Waldenström’s macroglobulinaemia. Other types of lymphoma can also affect the spleen. Tests are done so your doctor can diagnose exactly what type of lymphoma you have and what stage it is. Although it can be difficult waiting for the results of your tests, your doctor is collecting important information during this time. It is important that they know exactly what type of lymphoma you have so they can give you the most appropriate treatment.
Tests for splenic MZL usually include:
- a physical examination
- blood tests to look at your general health, your blood cell counts and to detect infections, such as hepatitis C
- a bone marrow biopsy, as abnormal cells are often found in the bone marrow
- a scan, usually a CT scan, to find out which parts of your body are affected by lymphoma.
A PET scan might be done if your specialist thinks it would be helpful in planning your treatment.
Sometimes, your spleen is removed when your medical team are trying to diagnose you. This operation is called ’splenectomy’. The removed tissue is examined and lymphoma cells may be found. You can live without a spleen but you do need to take some precautions to avoid infection.
Your blood tests also check for abnormal cells and proteins in your bloodstream, eg:
- villous lymphocytes (lymphocytes with finger-like projections on their surface)
- IgM (an abnormal antibody).
Stage describes how much of your body is affected by lymphoma.
- Stage 1 and 2 lymphomas are described as ‘early’ stage.
- Stage 3 and 4 lymphomas are described as ‘advanced’ stage.
Splenic MZL is usually stage 4 with bone marrow involvement when it is diagnosed.
Splenic MZL develops slowly. Most of the time, it cannot be cured but it is usually managed for many years with long periods where no treatment is needed.
Your doctor can give you more information about your prognosis (outlook) based on your individual circumstances.
Your treatment depends on whether the lymphoma is causing any problems and on your general health.
Most people have no symptoms at all or few symptoms. If this is the case, your doctor is likely to suggest monitoring you and keeping treatment until it is needed. This is called active monitoring or ‘watch and wait’. This approach allows you to avoid the side effects of treatment for as long as possible. Delaying treatment has no effect on how well it works when you do need it.
If you test positive for hepatitis C, you may be offered anti-viral treatment. Clearing the infection can also clear the lymphoma. Should this be the case, you might not need any more treatment.
Treatment is needed if your spleen is causing you discomfort or if your blood counts are very low. If you need treatment, you may have a splenectomy. This is a common treatment if you are fit enough for surgery and have not already had a splenectomy.
Many people with splenic MZL are diagnosed when they have a splenectomy. Around 9 in 10 people see a reduction in symptoms such as low blood counts after surgery. Typically, no further treatment is needed for several years.
Alternative treatments include:
Chemotherapy and antibody therapy are often used together as ‘chemo-immunotherapy’. People who are not fit enough for surgery or chemotherapy might be treated with rituximab alone, which can be very effective.
The most common chemotherapy for splenic MZL includes:
- a single chemotherapy drug, eg chlorambucil, cyclophosphamide, bendamustine or fludarabine
- a combination of chemotherapy drugs, eg CVP: cyclophosphamide, vincristine and the steroid prednisolone.
Your doctor might recommend a different regimen (combination of drugs), eg CHOP. CHOP may be an option for you if you have a lot of lymphoma.
If rituximab is given with chemotherapy, an ‘R’ is usually added to the name of the regimen, eg R-CVP.
The aim of treatment is to put you into remission (no evidence of lymphoma) for as long as possible. Your doctor should discuss with you the treatment they recommend.
Side effects of treatment
Treatments affect everyone differently. Each type of treatment or drug has a different set of possible side effects. Your medical team should give you more information about any side effects linked with your treatment. Ask for more information if you are worried about potential side effects. Your medical team can also help you manage side effects you get during your treatment if they become troublesome.
Precautions after a splenectomy
If you have had your spleen removed, you need to take extra precautions against infections because your body is less able to fight them. The risk of serious infection reduces with time but stays increased for the rest of your life.
Read all the information you are given about your operation and how to take care of yourself afterwards. Tell your GP, dentist and any other medical professional looking after you that you have had your spleen removed.
Contact your GP straightaway if you have any signs of infection, including but not limited to:
- fever (temperature above 38°C in adults)
- chills and sweating
- feeling generally unwell, confused or disoriented
- earache, cough, sore throat or mouth
- redness and swelling around skin sores or intravenous lines
- a burning or stinging sensation when passing urine
- unusual vaginal discharge or itching
- unusual stiffness of the neck and discomfort around bright lights
- severe headaches.
Splenic MZL can transform (change) into a faster-growing or more aggressive type of lymphoma. Overall, transformation happens in around 1 in 20 to 1 in 10 people with splenic MZL over the course of their disease.
Transformed splenic MZL is treated like a high-grade (fast-growing) non-Hodgkin lymphoma. The most common treatment is the chemo-immunotherapy regimen R-CHOP (rituximab, cyclophosphamide, doxorubicin [or hydroxydaunorubicin], vincristine [Oncovin®] and prednisolone).
During a period of active monitoring (‘watch and wait‘) or when you are in remission (no evidence of lymphoma) after your treatment, you have regular appointments in the clinic. Your doctor makes sure you are recovering well from treatment and that your lymphoma is still under control.
You are likely to be seen every 1–3 months at first. As long as you’re well, your follow-up appointments get less frequent over time until you are seen just once a year. You are likely to be followed-up for many years. How long your follow up lasts depends on your individual circumstances and your hospital’s policy.
You do not normally have scans at follow-up appointments unless you develop new symptoms.
It is common for splenic MZL to relapse (come back) after successful treatment. You can usually have more treatment to give another period of remission. This approach can often control the lymphoma for many years.
The same treatment options are usually used for relapsed splenic MZL as for untreated splenic MZL. However, new treatments are often tested first in people with relapsed or refractory lymphoma (lymphoma that didn’t respond to treatment). You may be able to enter a clinical trial of a new, targeted treatment.
Stem cell transplants are rarely used to treat splenic MZL. They are usually only considered if the lymphoma relapses soon after chemo-immunotherapy. A stem cell transplant allows you to have high doses of chemotherapy. It can give a better chance of a long-lasting remission (no evidence of lymphoma) than standard chemotherapy regimens. You must be fit enough to have this intensive form of treatment.
Splenic MZL is rare so most clinical trials include people with splenic MZL alongside other types of low-grade lymphoma. There are several newer, targeted treatments currently in clinical trials for marginal zone lymphomas, including drugs already approved for use in other types of lymphoma, eg:
Your doctor can advise whether there is a clinical trial that is suitable for you. You can find out more about clinical trials and search for a trial suitable for you at Lymphoma TrialsLink.