Chronic Lymphocytic Leukemia

Written by Camille Peri, K.A. Stump-Sutliff
Medically Reviewed by Elmer Huerta, MD, MPH on April 30, 2025
16 min read

Chronic lymphocytic leukemia (CLL) is a cancer that affects a type of white blood cell called lymphocytes.

Lymphocytes help your body fight infection. They're made in the soft center of your bones, called the marrow. If you have CLL, your body makes an abnormally high number of lymphocytes that aren't working right.

More adults get CLL than any other type of leukemia. It usually grows slowly, so you may not have symptoms for years.

Some people never need treatment, but if you do, it can slow the disease and ease symptoms. People who get medical care live longer now because doctors are diagnosing CLL earlier, and treatments are getting better.

It's natural to have worries and questions about any serious condition. You don't have to face things alone. Tell your friends and family about any concerns you have. Let them know how they can help. And talk to your doctor about how to join a support group. It can help to speak to people who understand what you're going through.

Doctors and researchers don't know what causes CLL. They do know that for some reason, changes happen in the DNA of your blood cells that make lymphocytes. When these changes (mutations) happen, your blood cells start to make abnormal cells that don't work the way they're supposed to.

As more abnormal lymphocytes live and multiply, they start to crowd out the healthy cells in your bone marrow. This keeps the marrow from producing healthy blood.

CLL risk factors

Some things could increase your risk of developing CLL. They include:

  • Having a parent, sibling, or child who has CLL
  • Being 50 or older
  • Being a White man
  • Having obesity
  • Having blood relatives who are either Eastern European or Russian Jews
  • Being exposed to Agent Orange, an herbicide widely used during the Vietnam War
  • Exposure to some other herbicides, such as: 
    • 2, 4 D
    • Atrazine
    • Diquat
    • Diuron
  • Being exposed to some insecticides (bug killers), such as: 
    • Chlorpyrifos
    • Endosulfan
    • Methomyl
    • Pyrethrin
  • Being exposed to some fungicides, such as:
    • Captan 
    • Thiram 
  • Being exposed to high levels of radiation
  • Breathing in benzene, a chemical solvent
  • Having monoclonal B-cell lymphocytosis (MBL), a condition that increases the number of a certain type of B cell in your blood

It's possible to find out you have CLL by accident, before you even have any symptoms. Routine blood tests done for a general physical exam or another medical issue might show abnormal results, making your doctor wonder whether you might have CLL.

Early CLL symptoms

If you look back, you may think of symptoms that you didn't pay attention to, such as fatigue or getting infections often. Chronic lymphocytic leukemia comes on slowly, and it can take decades before someone with CLL starts to show any symptoms. The symptoms are caused by the abnormal cells pushing out the healthy blood cells over time.

Other CLL symptoms

Over time, you may have:

  • Swollen lymph nodes in your neck, armpits, stomach, or groin (lymph nodes are pea-sized glands in these and other areas of your body.)
  • Shortness of breath
  • Pain or fullness in your stomach, which may be because the disease has made your spleen bigger
  • Extreme fatigue
  • Night sweats
  • Fever or chills that last more than two weeks but aren't caused by infections
  • Loss of appetite 
  • Loss of weight without trying to (more than 10% of your weight within six months)
  • An enlarged liver

CLL tests

If your doctor thinks you could have CLL, one of the first tests they will order is a complete blood count (CBC). This blood test checks how many red blood cells and white blood cells are circulating. It also measures the amount of hemoglobin, hematocrit, and platelets in your blood. Usually, another test called a peripheral blood smear is done at the same time. In the same sample of blood, the lab uses a microscope to look for lymphocytes that don't look the way they should.

Other possible blood tests include:

Flow cytometry. This looks for markers (special substances) that identify certain cells. The blood is colored with a fluorescent dye, which allows the lab technician to get a good look at the cells.

Blood chemistry, also called a blood panel. This measures electrolytes (such as sodium and potassium), as well as fats, proteins, enzymes, and glucose.

Lactate dehydrogenase testing. This checks for certain enzymes. If they are too high, this could mean there is tissue damage.

Beta-2-microglobulin testing. Beta-2-microglobulin is a small protein found on lymphocytes. If the test shows a higher-than-usual amount of beta-2-microglobulin, this could be a sign of some types of cancer.

Fluorescence in situ hybridization (FISH). This looks at the genes and chromosomes, which could show changes and abnormalities in chromosomes when you have cancer.

Gene mutation testing. This checks for any changes in one or multiple genes.

Serum immunoglobulin testing. This looks at specific antibodies in your blood.

Hepatitis B virus and hepatitis C virus testing. This checks to see whether you might have hepatitis instead of cancer.

HIV testing. It checks for HIV.

If your blood tests show anything that concerns your doctor, you will likely have to have some more tests so your doctor can diagnose you.

By checking the samples under a microscope for abnormal cells, your doctor can tell whether you have CLL and how fast it's moving. They can also learn more about the genetic changes in the cells. This information may help you and your doctor plan your treatment.

Other CLL tests

Imaging tests

Your doctor may choose to send you for some imaging tests before moving ahead with a biopsy.

  • CT scan. This is like a more in-depth X-ray that lets your doctor look at your organs and lymph nodes to see if they are larger than they should be.
  • PET/CT scan. A PET scan can be combined with a CT scan for a clearer view. A technician injects you with a liquid with a radioactive tracer that shows up on the images. Sometimes, doctors use this tracer to help them do a lymph node biopsy, so they can be more exact.
  • Ultrasound. It uses sound waves that bounce off your organs to form a picture on a screen that allows your doctor to check the size of your organs.

Biopsy

A biopsy is a test where a doctor removes some tissue or liquid and sends it to a lab for examination. Your doctor may recommend a bone marrow aspiration and biopsy and/or a lymph node biopsy.

Bone marrow aspiration and biopsy. These two tests are usually done together. In a bone aspiration, your doctor removes some samples of bone marrow from a bone, usually your hip. Your doctor will numb the area and then insert a fine needle into the bone. Using a syringe, the doctor removes some of the fluid — liquid bone marrow. 

For the bone marrow biopsy — usually done right after the aspiration — your doctor uses a slightly bigger needle to remove a very small piece of bone and marrow. These samples are sent to a lab for testing.

Lymph node biopsy. If your blood tests don't show clearly enough that you have CLL, your doctor may choose to do a lymph node biopsy. There are three ways to do that:

  • Excisional. A surgeon makes a cut in the skin to remove the entire lymph node and sends it to the lab.
  • Incisional. After making a cut, the surgeon removes only a small part of the lymph node to look at.
  • Fine needle aspiration (FNA) or core needle biopsy (CNB). Using a hollow needle (a fine one for FNA and a slightly larger one for CNB), the doctor removes some tissue from the lymph node. This type of lymph node biopsy is not the most accurate for diagnosing CLL, though.

Questions your doctor may ask

If you have one or more swollen lymph nodes, your doctor may ask:

  • Have you had any recent infections?
  • Have you had a recent injury?
  • Do you have an immune system disease?
  • Have you had a fever?
  • Are you short of breath?
  • Have you lost weight without trying to?
  • What medications do you take?

Questions to ask your doctor

  • What's the stage of my leukemia?
  • Do I need treatment now?
  • If not, how will we know when I need treatment?
  • Will I need other tests before we decide?
  • Should I get a second opinion?
  • What are the side effects of treatment?
  • How will it affect my daily life?
  • What will we do if the leukemia returns?

Unlike some other cancers, there aren't any specific types of CLL, but they are described in different ways.

  • Asymptomatic CLL is what someone may have if their CLL was discovered by accident — through a routine blood test, for example. If you have asymptomatic CLL, you don't have any symptoms.
  • Symptomatic CLL has progressed and is starting to cause symptoms or serious changes in your blood tests.
  • Recurrent CLL is when you have had CLL that went into remission but then came back, or recurred.
  • Refractory CLL doesn't get better despite treatment.

CLL is classified into different stages to help doctors know how to treat you. They look at how many lymphocytes you have, if you have any enlarged lymph nodes or organs, and if you have anemia or low platelet levels.

Two different staging systems are used: the Rai staging system and the Binet staging system. It's important to know which one is being used because if you have CLL and are talking to someone who has CLL or knows about it, using different staging scales can lead to confusion.

Rai staging system

  • Stage 0 (low risk). You have an abnormal amount of lymphocytes in your blood and bone marrow (lymphocytosis).
  • Stages I & II (intermediate risk). You have lymphocytosis with enlarged lymph nodes (stage I) or lymphocytosis with an enlarged spleen and/or liver (stage II).
  • Stages III & IV (high risk). You have lymphocytosis along with anemia (stage III) or lymphocytosis with low platelet counts, known as thrombocytopenia (stage IV).

Binet staging system

  • Stage A. You don't have anemia or thrombocytopenia, and fewer than three lymph nodes are swollen.
  • Stage B. You don't have anemia or thrombocytopenia, but you have three or more swollen lymph nodes.
  • Stage C. You have anemia and thrombocytopenia, as well as any number of swollen lymph nodes.

CLL doesn't have a cure, but treatment can put the cancer into remission, where there are no signs of active disease. This remission can last several years. Your doctor will choose a treatment plan based on the stage of CLL and how far it has advanced. Your doctor may have to change the treatment if it doesn't seem to be working or if you have a bad reaction to it and can't tolerate the treatment any longer.

Things that can affect which CLL treatment you get

The CLL treatment choices you have depend on how far it has advanced. Your doctor will take into account your blood test results, whether your lymph nodes, liver, or spleen are enlarged, your symptoms, and your overall health. Cancer treatment can cause serious side effects. So, if your health isn't great to begin with, this might limit what your doctor can choose to do.

Watchful waiting

Some types of CLL grow very slowly. If yours is in the early stages or not causing any problems, you probably don't need treatment but will instead be in a time of "watchful waiting." Your doctor will keep a close watch on you, so you should keep up with all your doctor visits. Your doctor will closely check to make sure your condition hasn't changed.

Chemotherapy (chemo)

These are drugs that kill or control cancer cells. Doctors often combine two or more drugs that work in different ways. You may get chemo by pill, shot, or IV. The drugs travel through your blood to reach and affect cells that are dividing too quickly all over your body. This includes certain healthy cells as well as cancer cells.

People usually get chemo in three- to four-week cycles that include a time of treatment and a time without treatment. The rest time gives your healthy cells time to rebuild and heal.

Side effects can include mouth sores, nausea, and low blood counts, which can increase your risk of bleeding or infection. Almost all side effects go away over time after treatment ends. And most chemo side effects can be treated or even prevented. If you have very serious side effects, you can talk to your doctor about adjusting your treatment plan.

Immunotherapy 

These drugs help your body's immune system find and destroy cancer cells. A type of immunotherapy called monoclonal antibodies is often used to treat CLL. They attach to certain proteins found on cancer cells and stimulate the immune system to destroy these cells. You get them through an IV or as a shot. Your doctor may give you this treatment on its own, but most people get it along with chemo.

Immunotherapy drugs cause different side effects than chemo does. Headaches, fevers, rashes, and blood pressure changes are just a few examples. Some can be prevented, and all can be treated.

Targeted therapy

These drugs block certain proteins in and on cancer cells that help them survive and spread. They target proteins found in your CLL cells and spare healthy cells. These drugs are taken as pills.

Side effects depend on which targeted therapy is used. They can include low blood counts, diarrhea, nausea, fatigue, and skin rashes. These can and should be treated. Most go away after treatment.

Much less often, one of these treatments may be used:

Radiation therapy

This type of treatment uses high-energy rays, such as X-rays, to destroy cancer cells. It may be used to shrink swelling in a lymph node or your spleen, or to treat bone pain.

Surgery

It's very rare, but if chemo or radiation doesn't shrink an enlarged spleen, surgery may be done to take it out. This can help improve blood cell counts.

Leukapheresis 

This is also a rare treatment. If you have a very high number of cancer cells in your blood at diagnosis, your doctor may use this treatment to lower them quickly. Your blood passes through a special machine that filters out the bad cells. This is a short-term fix, and you'll need other treatments, such as chemo or immunotherapy, to keep cancer cells under control.

Stem cell transplant

Researchers are studying new combinations of drugs and new ways of treating CLL to help people stay disease-free longer. One such treatment combines chemotherapy with a stem cell transplant.

Chemotherapy destroys cancer cells but also damages some healthy cells in the bone marrow.

The stem cell transplant supplies healthy young cells to help rebuild your immune system. You can get these cells from blood (a peripheral blood stem cell transplant, PBSCT), from bone marrow (which is used less now), or from umbilical cord blood.

Close relatives, such as your brother or sister, are most likely to be a good match. If that doesn't work out, you need to get on a list of potential donors from strangers. Sometimes, the best chance for the right stem cells for you will be from someone who has the same racial or ethnic background as you.

Before the transplant, you'll likely need to get treated with high doses of chemo for about a week or two. This can be a tough process because you may get side effects such as nausea and mouth sores.

When the high-dose chemo is done, you'll start the transplant. The new stem cells are given to you through an IV. You won't feel any pain from this, and you'll be awake while it's happening.

After your transplant, it could take two to six weeks for the stem cells to multiply and start making new blood cells. During this time, you may be in the hospital or will need to make visits every day to get checked by your transplant team. It can take six months to a year until the number of normal blood cells in your body gets back to what it should be.

Clinical trials often offer other treatment options. These are research studies that scientists use to find better ways to treat diseases. They may give you the chance to treat to try new treatments before they're available to everyone. You always get at least the best available treatment in a clinical trial, but you may also get access to a new approach that doctors think could be a promising way to treat CLL.

How to find a CLL clinical trial

If you're interested in taking part in a clinical trial or at least looking into one, first speak with your doctor. Your health care center may be running a trial or taking part in one. You can also search for clinical trials on your own, but it's important to keep in mind that not all people can take part in a trial. Each study has its own unique "inclusion" and "exclusion" requirements, which means to be part of the trial, you must fit into a certain group (such as have a certain stage), and there are things that might exclude you (such as receiving a specific type of medication in an earlier treatment). The CLL Society has a page that can help you find clinical trials in your area.

CLL treatment can cause side effects such as nausea and fatigue in some people. If it happens to you, let your doctor know, so you can manage the problems.

Ask your doctor about anti-nausea drugs. Therapeutic massage and acupuncture may also help control nausea and vomiting. Always check with your doctor before having acupuncture, though, because not everyone should have this type of treatment while getting cancer treatment.

Try walking, restorative yoga, breathing exercises, and meditation to curb fatigue and boost energy.

On days when your energy and mood are low, set one small goal for the day. Take a walk, talk with a friend, or take a relaxing shower.

Try these other ways to take care of yourself: 

  • Try to stay as active as possible, without overdoing it. This could be gardening, yoga, or simply going for a walk.
  • See if massage therapy may help you relax and relieve pain.
  • Learn as much about your cancer as is comfortable for you so you can make informed decisions.
  • Write down concerns and questions, and bring them to your appointments with you so you don't forget anything.
  • Bring someone with you to your appointments, such as a friend or family member, who can be your advocate and a second set of ears.
  • Join support groups, either online or in person, to talk about what is happening to you.
  • Talk to a therapist or counselor.
  • Ask for help from family and friends.

Other ways to take care of yourself involve trying to stay as healthy as possible. This can include:

  • Screenings for other types of cancer
  • Vaccinations to prevent certain infections. If you are getting treatment that lowers your immune system, always check with your doctor before getting any vaccine.
  • Seeing your family doctor or other specialists to monitor your health and treat any other medical problems you may have

CLL often grows slowly. With good care, you can live well with it for many years.

Things that can affect CLL prognosis

Overall, the average five-year survival rate after being diagnosed with CLL is almost 88%. That means 88 people out of 100 with CLL are still alive five years after their diagnosis. But the prognosis, or outlook, depends on some important things, including:

  • Your age
  • Your overall health. The state of your health, aside from the CLL, plays a role in the type of cancer treatment you can have and how well you tolerate it.
  • Other cancers (Have you gotten any other cancers since being diagnosed with CLL?)
  • The CLL stage
  • How well the treatment works (How quickly does the CLL respond to treatment? Unfortunately, sometimes CLL is refractory, which means it doesn't respond to treatment.)
  • Whether you have changes in certain genes, specifically TP53 or IgVH mutations
  • How low your red blood cell and platelet counts are
  • If your white blood cell count is rising quickly
  • Whether the CLL has worsened to another type of cancer called lymphoma

Tests that show how CLL has spread

While you are having CLL treatment, you will have to have regular tests to see if your body is responding to the treatment or if the CLL is spreading. These would be the same tests you might have had when you were first diagnosed:

  • Blood tests
  • Imaging tests
  • Bone marrow biopsies

If you have CLL, you are at risk of some complications as a result of the disease. These include:

Frequent infections. Your body's immune system can't fight infections as well as someone without CLL. On top of that, many of the treatments for CLL also weaken your immune system. Your doctor might recommend a treatment called immunoglobulin infusions, which can help your immune system.

Cancer progression. CLL can get worse and become a more aggressive cancer called diffuse large B-cell lymphoma, also called Richter's syndrome or Richter's transformation.

Other cancers. If you have CLL, your risk of developing another type of cancer, especially skin cancer, lung cancer, or cancers of the gastrointestinal tract, is higher.

Autoimmune thrombocytopenia or autoimmune hemolytic anemia. Sometimes, the immune system of people with CLL can attack their own healthy red blood cells or platelets by mistake. These are autoimmune disorders.

The Leukemia & Lymphoma Society has resources that can help you deal with different aspects of CLL, from financial to emotional issues. These resources include local education programs, support groups, online chats, and one-on-one support from someone who has been through it.

Chronic lymphocytic leukemia is usually a slow-growing type of cancer that people can have for several years before they have any symptoms. Even if you have some CLL symptoms, your doctor may decide it's better to watch and wait to see what happens before starting treatment. If you do need treatment, there are several options your doctor may choose from, tailoring the right treatment for you.

How long can you live with chronic lymphocytic leukemia?

Chronic lymphocytic leukemia doesn't have a cure, but treatment can often put it in remission. During this time, you won't have any signs of cancer. This remission can last years. If the cancer comes back, repeat treatment could put it back into remission.

Can you live normally with CLL?

Yes, you can. You might not have any symptoms or they may be minor for a long while. After the CLL goes into remission, you can probably live normally again.

What happens if CLL is left untreated?

Many times, doctors choose not to treat CLL, and they take a watchful waiting approach. During that time, the disease might not worsen at all or may get worse very slowly. But if the CLL is advanced and it's not treated, it will eventually be fatal.

Is chronic lymphocytic leukemia curable?

Generally, no, CLL is not curable. It is treatable and can go into remission, which means you won't have any signs of active cancer in your body. But it can come back.