About Chronic Lymphocytic Leukemia
Leukemia is a cancer of the white blood cells that arises from the bone marrow and circulates in the blood. It is characterized by uncontrolled growth of white blood cells. Leukemia is a disease of the blood cells and does not usually form a solid tumor. Although leukemia starts in the bone marrow, it can spread to the blood, lymph nodes, spleen, liver, central nervous system (CNS) and other organs.
There are four major types of leukemias:
- Acute myelogenous leukemia (AML)
- Chronic myelogenous leukemia (CML)
- Acute lymphocytic leukemia (ALL)
- Chronic lymphocytic leukemia (CLL)
The terms "myelogenous" and "lymphocytic" denote the different types of white blood cells involved. The terms "acute" or "chronic" refer to the rate of progression of the disease.
Chronic lymphocytic leukemia (CLL) represents approximately 33% of all leukemias and occurs most frequently in the elderly population. Approximately 66% of patients with CLL are 65 years of age older and the median age at the time of diagnosis is 72. Chronic lymphocytic leukemia usually does not develop in people under age 40 and is also extremely rare in children.
Chronic lymphocytic leukemia affects a particular type of white blood cells called B lymphocytes. For this reason, a more accurate name for this condition is B-cell chronic lymphocytic leukemia. Lymphocytes are specialized white blood cells of the immune system that play a major role in the body's ability to fight-off infections.
Although the exact cause of chronic lymphocytic leukemia is currently not known, researchers have recently discovered that certain mutations (genetic alterations or errors) that occur in the DNA of normal bone marrow cells can cause these cells to transform into leukemic cells.
Cytogenetic studies, which are special tests that can detect specific genetic mutations of chromosomes, have shown that patients with CLL often have a loss of part of a chromosome. This type of genetic mutation is called a deletion. In patients with CLL, the deletion is most often seen on chromosome 11 or 13. Other chromosomal abnormalities can also be detected in patients with CLL such as an extra chromosome 12 (trisomy 12).
In the early stages of the disease, clinical symptoms of chronic lymphocytic leukemia may not be obvious or may be overlooked by the patient. As the disease progresses, however, signs and symptoms become more evident. Patients may complain of generalized weakness or fatigue, may notice swollen lymph nodes, or develop recurring infections.
It is important to note, however, that approximately 50% of patients with CLL have no clinical symptoms of the disease at the time of presentation and that many cases of CLL are detected by a routine blood test in persons with no clinical symptoms. The major blood abnormality in people with CLL is an abnormal increase in the number of lymphocytes in the bloodstream, a condition known as lymphocytosis.
Chronic lymphocytic leukemia must be distinguished from other conditions that can cause similar signs and symptoms, including:
- Hairy cell leukemia
- Mantle cell leukemia
- B-cell prolymphocytic leukemia
- Leukemic phase of non-Hodgkin's lymphoma
- T-cell chronic lymphoproliferative disorders
Currently, with the possible exception of stem cell transplantation in younger patients, there is no know cure for chronic lymphocytic leukemia. Based on experience gained over the years in managing patients with CLL, doctors have developed the following general principles of treatment:
Because CLL is a chronic disease, it is often monitored for several years without the need for any treatment intervention.
In general, treatment is only initiated when there is clinical or laboratory evidence that the disease is progressing to a more advanced stage.
If treatment is indicated, patients should be offered the opportunity to participate in a clinical trial.
Patients with CLL who may benefit most from early, aggressive therapy include:
- younger patients
- patients in the more advanced stages of CLL
- patients with adverse prognostic factors
Patients with CLL are particularly at high risk for developing infections that, in some cases, may be life-threatening. The prevention and treatment of infections, therefore, is a primary goal in the management of patients with CLL.
Approximately 5% to 10% of patients with chronic lymphocytic leukemia develop a high-grade (aggressive) form of non-Hodgkin's lymphoma called a large B-cell lymphoma. This transformation of CLL to non-Hodgkin's lymphoma is known as Richter's syndrome or Richter's transformation. This disease transformation is often accompanied by symptoms such as fever, night sweats, weight loss, and enlargement of the lymph nodes, spleen, and liver. Richter's syndrome is usually treated with aggressive combination chemotherapy.
The prognosis (chance of recovery) for patients with chronic lymphocytic leukemia (CLL) can be difficult to predict with any degree of accuracy because of differences in the rate of progression of the disease between patients and individual variations in terms of response to treatment. In general, a majority of patients with CLL survive 5 to 10 years. Research has shown that, as a group, women with CLL tend to respond better to treatment and survive longer than men.
Factors that affect the prognosis for CLL patients include:
- The stage of the disease
- The extent of spread of lymphocytes within the bone marrow
- The patient's response to treatment
- Whether a patient develops serious complications such as recurrent infections or a secondary cancer
- The patient's overall health
The Medifocus Guidebook on Chronic Lymphocytic Leukemia is a unique, comprehensive patient education resource that contains vital information about Chronic Lymphocytic Leukemia that you won't find anywhere else in a single resource. The Guidebook will answer many of your questions about this condition that your healthcare provider may not have the time to answer. To learn more about the Guidebook, please click here
