Chronic lymphocytic leukemia (CLL) is a malignant lymphoproliferative disorder characterized by the progressive accumulation of mature but functionally abnormal B lymphocytes in the peripheral blood, bone marrow, lymph nodes, and other lymphoid tissues.

CLL is the most common leukemia in adults in many Western countries and has a variable clinical course ranging from an indolent disease requiring observation only to an aggressive disease requiring systemic treatment.

The disease causes:

• Progressive accumulation of abnormal lymphocytes

• Suppression of normal hematopoiesis

• Immune dysfunction leading to infections and autoimmune complications

Epidemiology

CLL occurs predominantly in older adults.

Epidemiological characteristics include:

• Most common leukemia in adults in many populations

• Usually affects individuals above 60 years

• Rare in children

• Slight male predominance

• Incidence increases with advancing age

Risk factors

Age

Advanced age is the strongest risk factor for CLL.

Genetic predisposition

Risk is increased in individuals with:

• Family history of CLL

• Genetic susceptibility affecting lymphocyte regulation

Chromosomal abnormalities

Common abnormalities include:

• Deletion 13q

• Deletion 11q

• Deletion 17p

• Trisomy 12

These abnormalities influence prognosis and treatment response.

Environmental factors

No specific environmental cause has been clearly established, although occupational and environmental exposures continue to be investigated.

Pathophysiology

CLL results from the malignant transformation of mature B lymphocytes.

The disease process involves:

1. Genetic changes causing abnormal lymphocyte survival

2. Accumulation of mature but ineffective B cells

3. Infiltration of bone marrow, lymph nodes, spleen, and blood

4. Suppression of normal blood cell production

The accumulation of leukemic lymphocytes causes:

• Anaemia due to reduced erythropoiesis

• Thrombocytopenia due to marrow replacement

• Immune dysfunction due to abnormal antibody production

CLL cells may also cause autoimmune complications, particularly:

• Autoimmune hemolytic anaemia

• Immune thrombocytopenia

Clinical presentation

CLL is often diagnosed incidentally during routine blood investigations.

Clinical presentation depends on:

• Disease stage

• Degree of lymphocyte accumulation

• Bone marrow involvement

• Immune complications

Symptoms

Constitutional symptoms

• Fatigue

• Fever

• Night sweats

• Unintentional weight loss

Symptoms due to lymphadenopathy

• Neck swelling

• Axillary swelling

• Groin swelling

• Abdominal fullness

Symptoms due to splenomegaly

• Left upper abdominal discomfort

• Early satiety

Symptoms due to cytopenias

Anaemia

• Weakness

• Shortness of breath

• Reduced exercise tolerance

Thrombocytopenia

• Easy bruising

• Bleeding tendency

Neutropenia

• Recurrent infections

Clinical signs

General examination

• Pallor

• Fever

• Weight loss

• Reduced performance status

Lymph node examination

• Generalized painless lymphadenopathy

Common sites include:

• Cervical lymph nodes

• Axillary lymph nodes

• Inguinal lymph nodes

Abdominal examination

• Splenomegaly

• Hepatomegaly

Skin examination

May reveal:

• Recurrent infections

• Skin infiltration in advanced disease

Differential diagnosis

• Reactive lymphocytosis due to viral infections

• Acute lymphoblastic leukemia

• Non-Hodgkin lymphoma with leukemic phase

• Mantle cell lymphoma

• Hairy cell leukemia

• Other chronic lymphoproliferative disorders

Diagnostic criteria

Diagnosis of CLL requires:

• Persistent increase in monoclonal B lymphocytes in peripheral blood

• Confirmation of B-cell clonality by flow cytometry

• Characteristic immunophenotype

Diagnosis is supported by:

• Peripheral blood lymphocytosis

• Bone marrow involvement when assessed

Investigations

Laboratory investigations

Full blood count (FBC)

May show:

• Persistent lymphocytosis

• Anaemia

• Thrombocytopenia in advanced disease

Peripheral blood film

May demonstrate:

• Increased mature lymphocytes

• Smudge cells

Immunophenotyping by flow cytometry

Used to confirm:

• B-cell lineage

• CLL-specific markers

Renal and liver function tests

Including:

• Urea

• Creatinine

• Liver enzymes

Performed before treatment.

Lactate dehydrogenase (LDH)

May assist in assessment of disease activity.

Direct antiglobulin test (DAT)

Performed when autoimmune hemolytic anaemia is suspected.

Imaging investigations

May include:

• Chest X-ray

• CT scan of chest, abdomen, and pelvis

Used to assess:

• Lymphadenopathy

• Organ involvement

Staging and classification

CLL is staged using:

Rai staging system

Classifies disease according to:

• Lymphocytosis

• Lymphadenopathy

• Hepatosplenomegaly

• Anaemia

• Thrombocytopenia

Binet staging system

Classifies disease according to:

• Number of involved lymphoid areas

• Presence of anaemia

• Presence of thrombocytopenia

Management

Management depends on:

• Disease stage

• Symptoms

• Rate of progression

• Cytopenias

• Presence of autoimmune complications

Many patients with early asymptomatic disease require observation only.

Management includes:

1. Active surveillance for asymptomatic patients

2. Chemotherapy or targeted therapy for symptomatic disease

3. Supportive treatment for complications

Non-pharmacological treatment

Observation and monitoring

Patients with early-stage asymptomatic disease should undergo:

• Regular clinical assessment

• Full blood count monitoring

• Assessment for disease progression

Supportive care

Includes:

• Infection prevention and prompt treatment

• Blood transfusion when clinically indicated

• Management of bleeding complications

Tumour lysis syndrome prevention

For patients receiving active therapy:

• Adequate hydration should be maintained

• Monitor renal function and electrolytes

• Consider uric acid-lowering therapy in high-risk patients

Pharmacological treatment

First-line treatment options

Treatment is indicated in patients with:

• Progressive disease

• Symptomatic lymphadenopathy

• Significant cytopenias

• Constitutional symptoms

• Progressive splenomegaly

Chlorambucil

Chlorambucil – 0.1 mg/kg – oral – once daily – for 2 weeks, followed by 2 weeks rest; repeat until remission is achieved

FCR regimen

Combination therapy with:

Fludarabine + cyclophosphamide + rituximab – intravenous – according to specialist chemotherapy protocol

Used in selected patients requiring combination therapy.

Autoimmune complications

Patients with autoimmune complications such as:

• Autoimmune hemolytic anaemia

• Autoimmune thrombocytopenia

require corticosteroid therapy.

Prednisolone – 1 mg/kg – oral – once daily – for 2 weeks

Management according to underlying cause

CLL with autoimmune hemolytic anaemia or autoimmune thrombocytopenia

Management includes:

• Corticosteroid therapy

• Monitoring of haemoglobin and platelet response

• Treatment of underlying CLL when autoimmune complications are persistent or recurrent

Advanced or progressive CLL

Patients with:

• Progressive cytopenias

• Symptomatic lymphadenopathy

• Severe constitutional symptoms

require systemic anti-leukemic therapy.

Referral

All suspected or confirmed CLL patients should be referred to specialist hematology services for diagnosis confirmation and treatment planning.

Urgent referral indications

• Severe anaemia

• Significant thrombocytopenia with bleeding

• Rapidly progressive lymphadenopathy

• Severe infections

• Autoimmune complications

• Suspected transformation to aggressive lymphoma (Richter transformation)

Complications

Disease-related complications

• Severe infections

• Anaemia

• Thrombocytopenia

• Autoimmune hemolytic anaemia

• Autoimmune thrombocytopenia

• Richter transformation to aggressive lymphoma

Treatment-related complications

• Myelosuppression

• Opportunistic infections

• Infusion reactions

• Immunosuppression-related complications

Prognosis

CLL has a highly variable prognosis.

Factors associated with prognosis include:

• Disease stage

• Cytogenetic abnormalities

• Response to therapy

• Presence of high-risk genetic markers

Many patients have prolonged survival, particularly those with early-stage disease.

Prevention

There are no established measures to prevent CLL.

Preventive strategies include:

• Avoid unnecessary exposure to radiation and carcinogenic substances

• Early evaluation of persistent lymphocytosis

• Regular monitoring of patients with known lymphoproliferative disorders