Chronic lymphocytic leukemia (CLL)

Disease information

Overview
Causes
and Symptoms
Treatment

Overview

Chronic Lymphocytic Leukemia (CLL) is a kind of blood cancer that involves the abnormal growth of lymphocytes, a type of white blood cell. These lymphocytes have lost their normal function and multiply uncontrollably.

CLL is typically a slow-progressing form of leukemia and is most commonly found in B lymphocytes, one of the two main types of lymphocytes, the other being T lymphocytes. Predominantly, CLL affects people over 60 years of age. While it's the most common type of blood cancer in Western countries, in South Korea, it's quite rare, accounting for only 0.4% of all cancer cases. This translates to an incidence rate of about 1.6 per 100,000 people.

Causes and Symptoms

No definitive risk factors for Chronic Lymphocytic Leukemia (CLL) have been identified so far. There's no confirmed link to viral infections or exposure to radiation. However, it's observed that the likelihood of developing CLL increases if there's a family history of CLL, Multiple Myeloma, or Lymphoma.

In many cases, there are no noticeable symptoms in the early stages of CLL. Often, it's detected during routine health check-ups or blood tests done for other reasons, when an unexpected increase in white blood cells (lymphocytes) is found and further examined.

Symptoms such as general weakness, fatigue, and loss of appetite
In progressive diseases, frequent fever and symptoms of infection like pneumonia
Enlargement of lymph nodes and internal organs
Dizziness, tinnitus, and fatigue due to anemia

▲ A symptom of fatigue

Treatment

In the early stages of Chronic Lymphocytic Leukemia (CLL), it's common to monitor the disease's progression rather than begin treatment immediately. Even if there's an increase in abnormal lymphocytes in the blood, or if there's swelling of the lymph nodes, liver, or spleen, treatment might not commence right away. Instead, the condition is closely observed. In fact, about 3 in 10 people may never require treatment during their lifetime.

The overall survival rate for Chronic Lymphocytic Leukemia (CLL) without treatment varies significantly based on the stage of the disease. On average, it stands at around 60-80% for 5 years, 20-30% for 10 years, and 10% for 20 years. When it comes to survival times based on the risk group, it's reported that the median survival time is about 15 years for those in the low-risk group. For individuals in the medium-risk group, the median survival time is estimated to be between 5-7 years. On the other hand, for those in the high-risk group, the median survival time is generally less than 3-4 years.

The following methods are used for the treatment of Chronic Lymphocytic Leukemia.

Anticancer (Immunological) Chemotherapy

This is a traditionally used method for treating typical B-cell Chronic Lymphocytic Leukemia, utilizing drugs like Chlorambucil or Fludarabine alone or in combination with monoclonal antibodies.

Hematopoietic Stem Cell Transplantation

This is a treatment method that replaces the diseased bone marrow, destroyed by leukemia, with healthy hematopoietic stem cells. Although autologous hematopoietic stem cell transplantation exists, there are almost no reports that it helps improve survival rates, so it is not applied to Chronic Lymphocytic Leukemia.

Latest Treatment Methods

a.
Targeted Anticancer Drugs
- Rituximab is actively used and is combined with other cytotoxic anticancer drugs. Recently, a new drug called Ibrutinib (Imbruvica) that selectively destroys the signal transmission system of B cells to kill cancer has been available for use under medical care benefits in Korea since 2018. For recurrent leukemia, a drug called Venetoclax that promotes cell death is used in combination with monoclonal antibodies to improve treatment outcomes.
b.
Chimeric Antigen Receptor T-cell (CAR-T) Therapy
- This is a cell therapy technique where T cells carrying an antigen receptor are manipulated to attack cancer. These immune cells find and attack cancer cells like guided missiles. It is a treatment method that is expected to be introduced and used in the near future.