Chronic lymphocytic leukemia (CLL)—a cancer of the blood and bone marrow—is the most common form of chronic leukemia in adults. About 20,000 people in the United States will develop CLL this year, according to the American Cancer Society.
Despite its prevalence, many people who have chronic lymphocytic leukemia actually don’t know it, because the disease often doesn’t present with any symptoms. “Chronic lymphocytic leukemia is a very slow-growing leukemia,” says Michal Bar-Natan Zommer, MD, assistant professor of hematology and oncology at Mount Sinai Hospital. “The majority of the patients are asymptomatic.”
For most cancers that don’t present obvious symptoms, the American Cancer Society recommends routine screening tests, because they are easier to treat it found early. Chronic lymphocytic leukemia, however, does not have routine screening tests.
“The majority of the patients [with CLL] will be discovered in accidental blood work that was done for something else,” says Dr Zommer.
Diagnosing Chronic Lymphocytic Leukemia
Blood tests. For example, a doctor may order a blood test called a complete blood count (CBC), which shows the number of red cells, white cells, and platelets in your blood. This test is used to diagnose and manage many diseases. If the results from a blood test show an increased number of lymphocytes, which are a type of white blood cell, it may be a sign that the person has CLL. Red blood cell and platelet counts may be low as well.
Immunophenotyping. If a doctor suspects CLL, they may also conduct a process called immunophenotyping, which compares cancer cells to normal immune cells. This test will determine whether a person’s lymphocytes are derived from a leukemia cells or other non-cancerous conditions.
Symptoms of CLL. Although many patients may not have symptoms initially, symptoms can develop—especially if the cancer spreads. “The cells growing in the [bone marrow and blood] eventually will grow in the lymph nodes, in the spleen, or in the liver,” says Dr. Zommer. Once CLL has spread to the lymph nodes, patients are more likely to experience leukemia symptoms.
“The first presentation can be [that] they feel lumps in their neck or elsewhere in their body,” says Dr. Zommer. “They can be tired because they have anemia, [or] they can have recurrent infection because their ability to fight infection is a little bit less.”
Chronic Lymphocytic Leukemia vs. Small Lymphocytic Lymphoma
Chronic lymphocytic leukemia and small lymphocytic lymphoma (SLL) share several characteristics, despite falling into two different types of blood cancer (leukemia and lymphoma). “[SLL] and CLL are actually the small disease that manifests a little differently,” says Michal Bar-Natan Zommer, MD, assistant professor of hematology and oncology at Mount Sinai Hospital.
Since both CLL and SLL affect lymphocytes and can affect the lymph system, the distinction depends on where the cancer is primarily located. “If the majority of the disease is in the lymph nodes or spleen—with less involvement in the blood and bone marrow—we call it small lymphocytic lymphoma,” says Dr. Zommer. If the cancer is mostly in the blood and bone marrow, it’s CLL.
Treatment for CLL and SLL may begin with the “watch and wait” method. “Some [patients] progress very slowly and the patient will not need treatment for many years,” says Dr. Zommer. If the cancer progresses to a stage that requires treatment, chemotherapy or biological therapies may be used. Learn more about types of treatment for blood cancer here.
“If you’re diagnosed with leukemia, it’s sometimes hard to cope … it’s changing your life. However, leukemia is curable and treatable,” says Dr. Zommer. “Fighting the cancer [has] become easier [and] more successful.”