Chronic lymphocytic leukemia (CLL) is the most common form of leukemia found in adults in the Western world. More people are living with CLL than any other type of leukemia. CLL starts from lymphocytes, white blood cells in the bone marrow, and then invades the blood. Although most types of CLL develop slowly in comparison to other types of leukemia, in time it can invade other parts of the body.
Another form of CLL grows faster and is a more serious disease. Fortunately, new lab tests can identify this class of CLL. At UC San Diego, Dr. Thomas Kipps has been the leading researcher on work with ZAP-70, a protein expressed mainly on the B cells of people with this more aggressive form of CLL. Dr. Kipps has found that ZAP-70 not only signals which patients may need treatment and which should not receive it, but that it may also offer important clues for developing new therapies.
The most common form of CLL starts in B lymphocytes. Some rare types of leukemia that share some features with CLL are:
- Prolymphocytic leukemia (PLL), a rare but aggressive form of the disease in which cancer cells are similar to normal cells called prolymphocytes – immature forms of B lymphocytes or T lymphocytes. Most cases respond to treatment but may relapse.
- Large granular lymphocyte (LGL) leukemia, in which the cancer cells are large and have features of either T lymphocytes or natural killer (NK) cells, which are another type of lymphocyte. These leukemias tend to be slow-growing, but a small number are more aggressive and difficult to treat.
- Hairy cell leukemia (HCL), a cancer of lymphocytes that accounts for about 2% of all leukemias, and which progresses slowly. At UC San Diego Health, Dr. Dennis Carson has developed a treatment for HCL that is effective in 75% of patients.
Many people with CLL feel well and live for years with good health. Because some CLL patients have disease that progresses slowly and they may not have symptoms, immediate treatment may not be needed. With their doctors, these patients undergo a “watch and wait,” or “watchful waiting” period with frequent follow-up exams to follow the disease progression. By looking at the number of CLL cells and whether or not your lymph nodes, spleen, or liver are enlarged, your doctor will determine the optimal treatment plan for you.
While there is no cure for CLL, there are a number of treatments, which usually begin when the number of CLL cells greatly increases, the number of normal cells decreases, the lymph nodes become larger, and/or the spleen becomes larger.
Chemotherapy and monoclonal antibodies
Patients with faster-progressing disease are usually treated with oral or injected drug therapy, called chemotherapy, which frequently combines two or more drugs for maximum efficiency together.
Another option is the use of monoclonal antibody therapy, a treatment with substances that are made naturally in the body. Some of these antibodies kill cancer cells themselves while others are joined to chemotherapy drugs or radioactive molecules and directed at cancer cells.
Blood and Marrow Transplant (BMT)
Blood and bone marrow transplantation (BMT) is a treatment option for CLL patients. The two primary types of BMT are autologous (using your own previously harvested cells) and allogeneic (using cells from a donor). Both are preceded by high-dose chemotherapy and/or radiation, which destroy not only the cancerous cells in your body, but healthy cells as well. You'll be in the hospital during this time, to ensure that you are not exposed to possible infection. Then, during the transplant procedure, you’ll receive healthy cells which make their way to your bone marrow and start producing new blood cells.
Radiation therapy is not a common treatment for CLL, but may be used if you have a very large mass of lymphocytes that are blocking your gastrointestinal or urinary tract. This cancer treatment uses high-energy x-rays or other types of radiation to kill cancer cells or prevent them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer, while internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The radiation method chosen for you depends on the exact type of the cancer being treated.
A splenectomy, which is surgery to remove the spleen, is used in a very small number of CLL patients when the spleen becomes filled with so many CLL cells that it causes discomfort or pressure.