Chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell).

Overview of CLL

Chronic lymphocytic leukemia is a blood and bone marrow disease that usually gets worse over time. CLL is the second most common type of leukemia in adults, often occurring in or after middle age.1

Normally, the body makes blood stem cells that slowly develop into mature blood cells, becoming a myeloid stem cell or a lymphoid stem cell. The myeloid stem cell develops into one of three types of mature blood cells:1

  • Red blood cells that carry oxygen and other materials body tissues
  • White blood cells that fight disease and infection
  • Platelets that help prevent bleeding by causing blood clots to form

The lymphoid stem cell develops into a lymphoblast cell and then into one of three types of lymphocytes:1

  • B lymphocytes that make antibodies to help fight infection
  • T lymphocytes that help B lymphocytes make antibodies to fight infection
  • Natural killer cells that attack viruses and cancer cells

In CLL, too many blood stem cells develop into abnormal lymphocytes and don’t result in healthy cells. The abnormal lymphocytes may also be called leukemic cells. The lymphocytes aren’t able to fight infection properly. Also, as the number of lymphocytes increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets.1


There are some signs and symptoms of CLL, but tests are needed to confirm diagnosis. A lot of people with CLL don’t have any symptoms at the time of diagnosis. The leukemia is often found when the doctor orders blood tests for some unrelated health problem or during a routine checkup.2

 Even when people with CLL have symptoms, they are often vague and non-specific, such as:2

  • Weakness
  • Feeling tired
  • Weight loss
  • Fever
  • Night sweats
  • Enlarged lymph nodes
  • Pain or a sense of "fullness" in the belly (especially after eating a small meal)

Many of the signs and symptoms of advanced CLL occur because the leukemia cells replace the bone marrow's normal blood-making cells. As a result, the body doesn’t make enough red blood cells, properly functioning white blood cells, and blood platelets. A symptom at this stage is anemia, which is a shortage of red blood cells, causing tiredness, weakness, and shortness of breath. A shortage of normal white blood cells (leukopenia) increases the risk of infections.  A shortage of blood platelets (thrombocytopenia) can lead to excess bruising, bleeding, frequent or severe nosebleeds, and bleeding gums.2 


The Canadian  Cancer Society's estimates for leukemia in Canada  for 2012 is approximately 5,600 new cases.3

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults.  It accounts for about one-third of all cases of leukemia4  with 1,600 new cases every year. Approximately 8,400 patients are currently living with CLL.  The average age at diagnosis is 67 years and it is rarely seen in children.5,6 

Seeking diagnosis and care

CLL diagnosis is made through blood tests. Typically people with early-stage CLL don't receive treatment, although clinical trials are currently evaluating whether early treatment may be helpful. Studies have shown that early treatment doesn't extend lives of people with early-stage chronic lymphocytic leukemia, so rather than put patients through the potential side effects and complications of treatment before they need it, doctors carefully monitor patients and reserve treatment for when the leukemia progresses (watchful waiting).7

If CLL progresses or is in the intermediate or advanced stages, treatment options include chemotherapy, targeted drug therapy or bone marrow stem cell transplant.4

Steps can also be taken to keep the body healthy by eating a healthy diet, getting enough sleep, not smoking and exercising.8


1. National cancer Institute. Chronic Lymphocytic Leukemia Treatment. Accessed 25/05/2012.

2. American Cancer Society. Leukemia-Chronic lymphocytic: early detection, diagnosis, and staging topics. Accessed 25/05/2012.

3. Canadian Cancer Society’s Steering Committee on Cancer Statistics. Canadian Cancer Statistics 2012. Toronto, ON: Canadian Cancer Society; 2012.

4. Statistics Canada. Table 103-0550 - New cases for ICD-O-3 primary sites of cancer (based on the July 2011 CCR tabulation file), by age group and sex, Canada, provinces and territories, annual (accessed: 18/07/2012)

5. Kipps TJ. Chapter 94. Chronic Lymphocytic Leukemia and Related Diseases. In: Prchal JT, Kaushansky K, Lichtman MA, Kipps TJ, Seligsohn U, eds. Williams Hematology. 8th ed. New York: McGraw-Hill; 2010. Accessed 25/05/2012.

6. American Cancer Society. Leukemia — chronic lymphocytic. Accessed 17/07/2012

Additional resources:

Leukemia & Lymphoma Society of Canada®

CLL Patient Advocacy Group

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