What is Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL)?
CLL and SLL are cancers that start in B cells—a type of white blood cell in the bone marrow. CLL and SLL are considered the same cancer, but differ based on where the cancer can be found. In CLL, many cancer cells are located in the blood and bone marrow. With SLL, cancer cells are mainly found in lymph nodes.
B cells form in the bone marrow and are released into the bloodstream to help the body fight off germs. B cells pass through the lymphatic system, which includes the lymph nodes and spleen.
With CLL/SLL, too many abnormal (or cancerous) B cells are created. This makes it difficult for healthy cells, like red blood cells, white blood cells, and platelets, to do their job. It can lead to symptoms like feeling tired or getting sick more often.
CLL is one of the most common leukemias in adults.
Approximately 19,000
new cases of CLL in the US in 2023
What are the types of CLL?
Doctors agree that there seem to be 2 different kinds of CLL:
- One that grows very slowly and may take a long time before cancer treatment is needed
- One that grows faster and is a more serious disease
Risk factors
Unlike other cancers, the risk of CLL does not seem to be linked to smoking, diet, or infections. There are very few known risk factors for CLL, but they include the following:
Aging
- Sex: CLL is slightly more common in males than in females
Race/ethnicity: there has been a higher incidence of CLL in non‑Hispanic White populations than in other racial groups
Family history of CLL or other blood and bone marrow cancers
Exposure to certain herbicides and insecticides
Please note that the risk factors listed above are not exhaustive.
