Chronic Lymphocytic Leukemia: Symptoms, Diagnosis, Treatment and Support
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is chronic lymphocytic leukemia?
Chronic lymphocytic leukemia, or CLL, is a type of leukemia that affects lymphocytes, a group of white blood cells, in the blood and bone marrow. It often progresses more slowly than some other leukemias, and symptoms may not appear at first. Diagnosis usually involves an exam and blood tests, and treatment depends on symptoms, disease extent, growth rate and health. [4]
What the research says
Targeted therapy beat chemotherapy as first treatment in older adults. In the RESONATE-2 trial of 269 previously untreated patients aged 65 or older, median progression-free survival was not reached with ibrutinib versus 18.9 months with chlorambucil (hazard ratio for progression or death 0.16). At 24 months, 98% of ibrutinib patients were alive versus 85%, and the overall response rate was 86% versus 35% (Burger et al., N Engl J Med, 2015). [1]
A time-limited combination worked well in relapsed or refractory disease. In the MURANO trial of 389 patients, 2-year progression-free survival was 84.9% with venetoclax plus rituximab versus 36.3% with bendamustine plus rituximab (hazard ratio 0.17, 95% CI 0.11 to 0.25). Grade 3 or 4 tumor lysis syndrome occurred in 3.1% of patients receiving venetoclax plus rituximab (Seymour et al., N Engl J Med, 2018). [2]
Two targeted drugs had similar effectiveness in previously treated disease, with different side-effect profiles. In a randomized phase 3 trial of 533 previously treated patients with del(17p) or del(11q), median progression-free survival was 38.4 months in both the acalabrutinib and ibrutinib arms (hazard ratio 1.00, 95% CI 0.79 to 1.27). Atrial fibrillation occurred in 9.4% versus 16.0%, and discontinuation because of adverse events in 14.7% versus 21.3% (Byrd et al., J Clin Oncol, 2021). [3]
What Is Chronic Lymphocytic Leukemia?
Chronic lymphocytic leukemia is a type of leukemia. Leukemia is a cancer that affects blood and bone marrow, the spongy tissue inside bones where blood cells are made. [4]
The word chronic refers to the fact that CLL often progresses more slowly than some other leukemias. Lymphocytic refers to lymphocytes, a group of white blood cells that help the body fight infection. [4]
In CLL, cancer cells can build up in the blood, bone marrow, lymph nodes and other parts of the body. [4]
What Symptoms Can CLL Cause?
Chronic lymphocytic leukemia (CLL) symptoms may not happen right away, so the disease can be present without obvious signs. When they do occur, they may include:
These symptoms can have causes other than CLL. An online article cannot determine the cause of an individual symptom.
When Should You See a Healthcare Professional?
Make an appointment with a healthcare professional if you have symptoms that worry you, including unexplained swollen lymph nodes, repeated infections, persistent fatigue, fever, night sweats or unintentional weight loss.
Symptoms do not prove that someone has CLL. A professional evaluation may include an examination and testing to understand what is causing them.
What Causes CLL?
The cause of chronic lymphocytic leukemia is not clear. Cancer develops when cells acquire changes in their DNA, which contains the instructions that tell cells how to behave. [4]
In healthy cells, DNA helps control how cells grow, multiply and die. In cancer cells, DNA changes can cause cells to multiply too much and continue living when healthy cells would normally die. This creates an excess of cells. [4]
In CLL, the abnormal cells are lymphocytes that may accumulate in the blood, bone marrow, lymph nodes and other areas. [4]
What Are the Risk Factors?
Chronic lymphocytic leukemia (CLL) risk may be increased by a number of different factors. [4]
Risk factor | Details |
Age | CLL occurs most often in adults older than 55. |
Race | White people are more likely to develop CLL than people of other races. |
Family history | A family history of CLL or other blood and bone-marrow cancers may increase risk. |
Chemical exposure | Certain herbicides and insecticides, including Agent Orange, have been linked to increased risk. |
Monoclonal B-cell lymphocytosis | MBL increases the number of B lymphocytes in the blood, and a small number of people with MBL may develop CLL. |
A risk factor does not prove that someone will develop CLL. People without a risk factor may still develop the disease.
How Is Chronic Lymphocytic Leukemia Diagnosed?
Diagnosis often begins with a physical exam. A healthcare professional may check for swollen lymph nodes in the neck, underarms and groin, as well as an enlarged spleen.
Blood Tests
Test | General purpose |
Complete blood count | Counts cells in a blood sample, including lymphocytes. A high number of B cells may suggest CLL. |
Peripheral blood smear | Shows the size, shape and appearance of blood cells. It may show many small, round lymphocytes, sometimes called smudge cells. |
Cell-surface protein testing | Identifies markers on cancer cells that can help identify them and may help predict how aggressive they are. |
DNA testing | Looks for DNA changes in leukemia cells. |
Other Tests
A healthcare team may recommend additional tests to clarify a diagnosis or guide care.
The exact testing plan depends on the person's symptoms, examination and test results.
What Treatments Are Used for CLL?
Treatment depends on whether symptoms are present, the extent or stage of the cancer, how quickly it is growing, overall health and personal preferences. [5]
Treatment or approach | General role |
Watchful waiting | Regular checkups when CLL does not cause symptoms and immediate treatment is not needed. |
Targeted therapy | Medicines that attack specific proteins in cancer cells. |
Chemotherapy | Strong medicines that kill cancer cells and may be used in selected situations. |
Immunotherapy | Medicines that help the immune system find and kill cancer cells. |
Bone-marrow transplant | Replaces damaged marrow cells with healthy stem cells and may be considered in some relapsed or refractory cases. |
CAR-T cell therapy | Modifies a person's T cells to recognize and destroy leukemia cells; may be used for some relapsed or refractory CLL. |
Radiation | May be used to ease symptoms and improve quality of life. |
Clinical trials | Studies of new treatments whose risks and benefits may not yet be known. |
A healthcare team must explain which options apply to a particular person and what benefits, risks and side effects may be involved.
What Is Watchful Waiting?
If CLL does not cause symptoms, treatment may not be needed right away. Instead, a healthcare team may schedule checkups every few months to watch for progression. [5]
Watchful waiting is not a decision that can be made from an online article. Whether monitoring is appropriate depends on clinical findings and the treatment plan created with the healthcare team.
Targeted Therapy
Targeted therapy uses medicines that attack specific proteins in cancer cells. By blocking these proteins, the treatment can cause cancer cells to die. [5]
Targeted therapy is often a first treatment for CLL. It may also be used when earlier treatment has not worked or when the cancer returns. [5]
Possible side effects include diarrhea, liver problems, high blood pressure, problems with blood clotting or wound healing, fatigue, mouth sores and nail changes. [5]
Chemotherapy
Chemotherapy uses strong medicines to kill cancer cells. It may be given through a vein or as a pill. [5]
Chemotherapy may be used in selected situations, including when targeted therapy cannot be tolerated or when CLL has transformed into a more aggressive cancer. Side effects depend on the medicines used and may include nausea and hair loss. Serious long-term complications can occur.
Immunotherapy
Immunotherapy helps the immune system recognize and kill cancer cells. It may be combined with chemotherapy or used for relapsed or refractory CLL. [5]
Possible side effects include fever, chills, weakness, dizziness, aches, upset stomach and vomiting. Rarely, some immunotherapy treatments can cause an allergic reaction. [5]
Bone-Marrow Transplant
A bone-marrow transplant, also called a bone-marrow stem-cell transplant, puts healthy stem cells into the body to replace cells damaged by treatment. [5]
An autologous transplant uses a person's own stem cells. An allogeneic transplant uses cells from a donor. An allogeneic transplant may be an option for some people with relapsed or refractory CLL, but transplants are less common as newer treatments develop. [5]
CAR-T Cell Therapy
CAR-T cell therapy removes some white blood cells, including T cells, and sends them to a laboratory. The cells are changed to make receptors that recognize markers on leukemia cells. The cells are then returned to the body. [5]
CAR-T cell therapy may be an option for some people with relapsed or refractory CLL, often after at least two other treatments. Possible side effects include fever, stomach upset, headache, confusion, dizziness, rash, fast heartbeat, trouble breathing and low blood pressure. [5]
Radiation and Clinical Trials
Radiation therapy uses powerful energy beams and may be used to ease symptoms and improve quality of life. Side effects vary by the part of the body treated. [5]
Clinical trials study new treatments. They may offer access to newer approaches, but risks and side effects may not yet be known. Ask the healthcare team whether a clinical trial may be appropriate. [5]
What Complications Can CLL or Its Treatment Cause?
CLL and its treatments may lead to serious complications. Some complications can be serious and require prompt professional attention. [4]
Frequent or serious infections: CLL may reduce germ-fighting antibodies, and treatment may suppress the bone marrow.
Febrile neutropenia: A serious condition involving fever and low neutrophils during cancer treatment.
Medicine toxicity: Some medicines can damage organs or cause other health problems.
Viral reactivation: Some treatments may reactivate previous infections such as hepatitis B or hepatitis C.
Tumor lysis syndrome: Rapid breakdown of cancer cells can release substances that overwhelm the body and harm organs.
Transformation: A small number of people may develop a more aggressive cancer called diffuse large B-cell lymphoma, sometimes called Richter syndrome. [4]
Other cancers: People with CLL have an increased risk of some other cancers. [4]
Immune-system attacks: The immune system may mistakenly attack red blood cells or platelets. [4]
Seek prompt professional help for symptoms that could signal a serious complication, especially during treatment. Follow the instructions of the healthcare team.
What Happens After Treatment?
After treatment, follow-up appointments may be used to check whether the cancer has returned, called a relapse. Follow-up may include repeat blood tests and imaging. [5]
The timing and type of follow-up depend on the person's treatment and clinical situation. Ask the healthcare team what symptoms, tests and appointments should be expected.
How can people cope with chronic lymphocytic leukemia (CLL)?
A CLL diagnosis can create uncertainty and worry. It may help to learn enough about the condition to participate in care decisions, while avoiding information that becomes overwhelming.
Support may include:
Staying connected with friends and family.
Asking for practical help at home or during appointments.
Talking with a counselor, social worker, faith leader or support group.
Writing down questions and bringing someone to appointments.
Asking the healthcare team about local or online support resources.
No alternative treatment has been proved to cure CLL. Some approaches, such as exercise, massage, yoga or acupuncture, may help some people cope with fatigue, but discuss them with a healthcare professional.
How Can You Prepare for an Appointment?
Before an appointment, ask whether you need to do anything in advance.
Bring or write down:
Your symptoms and when they began.
Whether symptoms are constant or occasional.
Any fever, night sweats, weight loss, lumps, swelling or pain.
Other health conditions and recent stresses or life changes.
Medicines, vitamins and supplements, including doses.
Your questions, listed from most important to least important.
A friend or family member, if helpful.
Questions may include:
Do I have CLL?
What tests do I need?
What is the stage or extent of the disease?
Will I need treatment now or monitoring first?
What treatment options are available?
What side effects could occur?
Should I see a blood or bone-marrow specialist?
Are there clinical trials that may be appropriate?
Frequently Asked Questions
What is chronic lymphocytic leukemia?
Chronic lymphocytic leukemia is a cancer of blood and bone marrow that affects lymphocytes. It often progresses more slowly than some other leukemias.
What are the symptoms of chronic lymphocytic leukemia?
Possible symptoms include swollen lymph nodes, fever, drenching night sweats, fatigue, unexplained weight loss, appetite loss, upper-left abdominal pain and frequent infections. Symptoms may not appear at first.
How is CLL diagnosed?
Diagnosis may include a physical exam, complete blood count, peripheral blood smear, cell-surface protein testing, DNA testing, bone-marrow testing and imaging. The testing plan depends on clinical findings.
What is watchful waiting for CLL?
Watchful waiting means regular checkups when CLL does not cause symptoms and immediate treatment is not needed. It is a healthcare-team decision based on symptoms, tests and the disease's behavior.
What treatments are used for chronic lymphocytic leukemia?
Options may include targeted therapy, chemotherapy, immunotherapy, stem-cell transplant, CAR-T cell therapy, radiation and clinical trials. Treatment depends on the disease and the person's overall health and preferences.
Can chronic lymphocytic leukemia come back after treatment?
CLL can relapse in some people. Follow-up visits, blood tests and imaging may help the healthcare team monitor for a return of disease.
What complications can CLL cause?
Possible complications include infections, febrile neutropenia, medicine toxicity, viral reactivation, tumor lysis syndrome, more aggressive disease and immune-system attacks on blood cells. The risk depends on the disease and treatment.
When should you see a doctor about possible CLL symptoms?
Make an appointment if you have symptoms that worry you, such as persistent swollen lymph nodes, repeated infections, fever, night sweats, fatigue or unexplained weight loss. Only professional evaluation can determine the cause.
Conclusion: What to Remember About CLL
Chronic lymphocytic leukemia is a slower-progressing leukemia that affects lymphocytes in the blood and bone marrow. Some people have no symptoms at first, while others develop swollen lymph nodes, fatigue, infections, fever, night sweats, weight loss or abdominal discomfort.
Diagnosis may involve blood tests, cell and DNA testing, imaging and sometimes bone-marrow testing. Treatment ranges from monitoring to medicines, transplant, CAR-T therapy, radiation or clinical trials, depending on the person's symptoms, disease extent, growth rate, health and preferences.
If you have concerning symptoms or questions about a test result, make a plan with your healthcare team rather than relying on a general article.
References
Burger JA, Tedeschi A, Barr PM, et al. Ibrutinib as initial therapy for patients with chronic lymphocytic leukemia. N Engl J Med. 2015;373(25):2425-2437. PMID: 26639149. DOI: 10.1056/NEJMoa1509388
Seymour JF, Kipps TJ, Eichhorst B, et al. Venetoclax-rituximab in relapsed or refractory chronic lymphocytic leukemia. N Engl J Med. 2018;378(12):1107-1120. PMID: 29562156. DOI: 10.1056/NEJMoa1713976
Byrd JC, Hillmen P, Ghia P, et al. Acalabrutinib versus ibrutinib in previously treated chronic lymphocytic leukemia: results of the first randomized phase III trial. J Clin Oncol. 2021;39(31):3441-3452. PMID: 34310172. DOI: 10.1200/JCO.21.01210
Mayo Clinic Staff. Chronic lymphocytic leukemia: Symptoms and causes. Mayo Clinic. October 25, 2025. https://www.mayoclinic.org/diseases-conditions/chronic-lymphocytic-leukemia/symptoms-causes/syc-20352428
Mayo Clinic Staff. Chronic lymphocytic leukemia: Diagnosis and treatment. Mayo Clinic. October 25, 2025. https://www.mayoclinic.org/diseases-conditions/chronic-lymphocytic-leukemia/diagnosis-treatment/drc-20352433
Disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition.
It is educational content, not a diagnosis, prognosis or personalized treatment plan. A qualified healthcare professional should interpret symptoms and test results, decide whether monitoring or treatment is appropriate, and advise on side effects and complications. Seek prompt professional help for symptoms that could signal a serious complication, especially during treatment.
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