Health Guide

Chronic lymphocytic leukemia (CLL)


Chronic lymphocytic leukemia (CLL) is cancer of a type of white blood cells called lymphocytes. These cells are found in the bone marrow and other parts of the body. Bone marrow is the soft tissue in the center of bones that helps form all blood cells.

CLL causes a slow increase in a certain type of white blood cells called B lymphocytes, or B cells. Cancer cells spread through the blood and bone marrow. CLL can also affect the lymph nodes or other organs such as the liver and spleen. CLL eventually can cause the bone marrow to lose its function.

Alternative Names

CLL; Leukemia - chronic lymphocytic (CLL); Blood cancer - chronic lymphocytic leukemia; Bone marrow cancer - chronic lymphocytic leukemia; Lymphoma - chronic lymphocytic leukemia


The cause of CLL is unknown. There is no link to radiation. It is unclear if certain chemicals can cause CLL. Exposure to Agent Orange during the Vietnam War has been linked to a slight increased risk of developing CLL.

CLL usually affects older adults, especially those over age 60. People under age 45 rarely develop CLL. CLL is more common in whites than in other ethnic groups. It is more common in men than in women. Some people with CLL have family members with the disease.


Symptoms usually develop slowly. CLL is often found by blood tests done in people for other reasons or who do not have any symptoms.

Symptoms of CLL may include:

Exams and Tests

The health care provider will perform a physical exam and ask about your symptoms.

Tests to diagnose CLL may include:

People with CLL usually have a high white blood cell count.

Tests that look at changes in the DNA inside the cancer cells may also be done. Results from these tests and from staging tests help your provider determine your treatment.


If you have early stage CLL, your provider will just monitor you closely. Treatment is not generally given for early-stage CLL, unless you have:

  • Infections that keep coming back
  • Leukemia that is rapidly getting worse
  • Low red blood cell or platelet counts
  • Fatigue, loss of appetite, weight loss, or night sweats
  • Swollen lymph nodes

Chemotherapy, including targeted medicines, are used to treat CLL. Your provider will determine which type of medicines are right for you.

In rare cases, radiation is used for painful and enlarged lymph nodes.

Blood transfusions or platelet transfusions may be required if blood counts are low.

Bone marrow, or stem cell transplantation may be used in younger people with advanced or high-risk CLL. A transplant is the only therapy that offers a potential cure for CLL, but it also has risks. Your provider will discuss the risks and benefits with you.

You and your provider may need to manage other concerns during your leukemia treatment, including:

  • Having chemotherapy at home
  • Managing your pets during chemotherapy
  • Bleeding problems
  • Dry mouth
  • Eating enough calories
  • Safe eating during cancer treatment

Support Groups

You can ease the stress of illness by joining a cancer support group. Sharing with others who have common experiences and problems can help you not feel alone.

Outlook (Prognosis)

Your provider can discuss with you the outlook of your CLL based on its stage and how well it responds to treatment.

Possible Complications

Complications of CLL and its treatment may include:

  • Autoimmune hemolytic anemia, a condition in which red blood cells are destroyed by the immune system
  • Bleeding from low platelet count
  • Hypogammaglobulinemia, a condition in which there is a lower level of antibodies than normal, which can increase the risk of infection.
  • Idiopathic thrombocytopenic purpura (ITP), a bleeding disorder 
  • Infections that keep coming back (recur)
  • Fatigue that can range from mild to severe
  • Other cancers, including a much more aggressive lymphoma (Richter transformation)
  • Side effects of chemotherapy

When to Contact a Medical Professional

Call a provider if you develop enlarged lymph nodes or unexplained fatigue, bruising, excessive sweating, or weight loss.


Byrd JC, Flynn JM. Chronic lymphocytic leukemia. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff's Clinical Oncology. 5th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 102.

National Cancer Institute website. Chronic lymphocytic leukemia treatment (PDQ) - health professional version. Updated January 20, 2017. Accessed September 29, 2017.

National Comprehensive Cancer Network website. NCCN clinical practice guidelines in oncology: chronic lymphocytic leukemia/small lymphocytic lymphoma. Version 1.2018. Updated August 21, 2017. Accessed September 29, 2017.

Review Date: 8/14/2017
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.