Chronic lymphocytic leukaemia (CLL) is a blood cancer which affects the bone marrow and white blood cells. This type of cancer develops more slowly than other types of leukaemia and is the most prevalent subtype of leukaemia in Western countries, causing considerable health burden on patients.

Signs and symptoms

Commonly there are no symptoms in the early stages of the disease, however these are some which may develop as the cancer advances:

• Enlarged painless lymph nodes.
• Fatigue
• Fever
• Pain in upper left portion of the abdomen. This may be caused by an enlarged spleen.
• Night sweats
• Weight loss
• Frequent infections

Cause

The specific cause of CLL is unknown, however it is suggested that mutations occur to the DNA of blood-producing cells. These mutations instruct the blood cells to produce abnormal, ineffective lymphocytes.

When there is an abundance of abnormal lymphocytes, they may crowd healthy lymphocytes and causing them to die. This can cause problems in the blood and organs of the body.

Risk factors

Some factors which may increase the risk of developing CLL include:

• Age – commonly affects older adults.
• Race – it is more likely to develop among white people.
• Genetics – a family history of any type of blood or bone marrow cancers.
• Chemicals – contact with certain herbicides and insecticides have been linked with an increased risk.

Statistics (Global Burden of Disease Study 1990-2019)

• CLL accounts for 25-30% of all the leukaemia in Western countries.
• Males are approximately two times likely to develop CLL than females. 

	1990	2019
Incidence of cases	40,537	103,467
Global deaths	21,548	44,613
Disability-adjusted life years (DALY) cases	492,075	948,464

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References

• The global burden and attributable risk factors of CLL ... 2022.pdf
• Chronic lymphocytic leukemia - Symptoms and causes - Mayo Clinic