Chronic Lymphocytic Leukemia (CLL)
Chronic lymphocytic leukemia (CLL) is a malignant disease of the blood (leukemia),
characterized by the proliferation of lymphocytes (type of white
blood cells made in the bone marrow) which places it in the
category of chronic lymphoid malignancies. This is the most common leukemia, affecting preferentially the
elderly over 50 years old. Apart from a few familial cases, there are no known factors favoring the onset of the
disease: environmental, genetic or infectious. This condition is incurable so far, but the prognosis is extremely variable from one
patient to another. For 60% of patients it is not necessary to start treatment at initial diagnosis of the
disease due to its slow scalability.
leukemia is defined by the monoclonal proliferation of a population of mature B lymphocytes. These cells will
gradually invade the blood, lymphoid organs, and the bone marrow. But the cellular mechanisms
inducing lymphocyte proliferation are not completely understood.
Causes of Chronic
In chronic lymphocytic leukemia, the male / female ratio is 2 /1 and the peak
frequency is around the age of 65. CLL is rare before age 40, and affects a patient over 50 years in 90% of
cases. This is the most common chronic leukemia in Western countries; the incidence is
estimated at 3.5 new cases per 100,000 people in the United States. It is rarer in the Far East.
leukemia appears to be a familial predisposition with a three -fold increased risk if a sibling is affected
by the tumor. It does not seem to have environmental
triggers with the exception of exposure to defoliant, a chemical that is
sprayed on plants to cause their leaves fall off. Similarly, the potentiating role of irradiation remains
controversial. Repeated infections, especially in the lung however, appear to be a risk factor for
the disease, probably due to an iterative stimulation of the immune system.
Symptoms of Chronic
In about one third of
chronic lymphocytic leukemia cases, there are no clinical signs of the disease at the
beginning. The disease is often discovered during blood test such as complete blood count
(CBC). The most common clinical signs or symptoms tend to be discovered by the patient
himself or during an examination of a superficial lymphadenopathy (disease of the
lymph nodes) or splenomegaly
(increased spleen volume). More rarely, the diagnosis is straightforward to an infectious complication or an
The presence of fever,
night sweats or poor general condition can be a warning sign indicating that the patient must immediately
seek medical care to confirm or rule out underlying infection, transformation of CLL in high-grade lymphoma
Richter's syndrome) or cancer related
to other organs.
Survival Rates and Treatment