Chronic lymphocytic leukemia (CLL)
Causes and risk factors
It is the most common form of leukemia in adults in Western society, accounting for 20-25% of all leukemias. Incidence is about 2-6 new cases a year per 100,000 people.
CLL is twice as common in men. The average age at diagnosis is 65, but about a third of patients are younger than 55. Before the age of 25 it occurs very rarely.
There is a genetic predisposition to the disease, and in about 5-10% of cases, there is a family history of several members of the same family having the disease (or other lymphomas).
Causes of the disease are unknown, and CLL is not associated with known environmental factors, such as exposure to ionizing radiation, chemical agents, or medications.
Accumulation of leukemic cells in bone marrow leads to a decrease in hemoglobin and platelet levels, and accumulation in lymph nodes, spleen, and liver leads to enlargement of these organs.
Which are the symptoms?
About 25% of patients are asymptomatic. The onset of the disease may be characterized by enlarged lymph nodes and/or elevated lymphocytes in the blood, which can sometimes be seen during simple check-ups. There may also be a decrease in hemoglobin (anemia) and/or platelets (thrombocytopenia). Enlargement of lymph nodes occurs in about 80% of patients; lymphadenopathies mostly affect superficial (lateral, supraclavicular, or axillary) lymph nodes. Approximately half of patients have an enlarged spleen (splenomegaly), which can sometimes result in symptoms such as premature fullness and/or a full stomach.
In other cases, minor symptoms may be present, such as:
- decreased tolerance for effort
- nonspecific malaise.
Patients with a progressive disease may have:
- unexplained weight loss;
- recurrent infections;
- night sweats;
- body temperature above 38°C.
How is it diagnosed?
At diagnosis, the absolute number of lymphocytes in the blood usually exceeds 10,000/mmc, sometimes 100,000/mmc.
The following is also present:
- anemia of varying degrees (about 15% of patients);
- autoimmune hemolytic anemia (about 8% of patients);
- positive Coomb’s test (about 20% of patients);
- decreased platelet level (about 10% of patients);
- autoimmune thrombocytopenia (about 5-7% of patients).
The bone marrow invariably has a leukemic cell infiltrate with nodular (10% of cases), diffuse (25% of cases), interstitial (33% of cases), or mixed (25% of cases) type. The involved lymph nodes have a diffuse infiltrate of small lymphocytes.
How is it treated?
Patients who are asymptomatic and have only elevated lymphocyte levels do not need treatment, regardless of the number of circulating lymphocytes in the blood. However, periodic outpatient examinations are necessary to assess the possible evolution (growth) of the disease over time.
If patients develop symptoms at diagnosis or at follow-up (for example, due to anemia, thrombocytopenia, massive lymphadenopathy, or general symptoms), treatment should be carried out in the form of chemotherapy (pills or intravenous infusions) with or without immunotherapy (monoclonal antibodies). The drugs used (alone or in combination) depend mainly on the age and clinical situation of patients.
In individual cases, mostly in young people with an aggressive course of the disease, stem cell transplantation (from a compatible donor) may be considered.