Acute Leukaemia

Overview

Acute leukaemia represents a heterogeneous group of haematological malignancies characterized by clonal proliferation of immature haematopoietic precursor cells (blasts) in the bone marrow and peripheral blood. [1] The disease fundamentally disrupts normal haematopoiesis, leading to bone marrow failure with consequent pancytopenia and its associated complications. [2] The two principal subtypes—acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL)—differ substantially in their molecular pathogenesis, age distribution, treatment approaches, and prognosis. [3]

Key Clinical Facts

Epidemiology:

• AML: Median age 68 years, incidence 4.3 per 100,000 in adults
• ALL: Bimodal distribution (peak ages 2-5 years and > 50 years), incidence 1.7 per 100,000
• Male predominance in both subtypes (M:F ratio approximately 1.4:1)
• Incidence increases with age for AML, accounting for 80% of adult acute leukaemias

Clinical Presentation:

• Symptoms of bone marrow failure: fatigue (anaemia), infections (neutropenia), bleeding/bruising (thrombocytopenia)
• Duration of symptoms typically 2-12 weeks before diagnosis
• Organ infiltration possible (hepatosplenomegaly, lymphadenopathy, CNS involvement in ALL)
• Emergency presentations: neutropenic sepsis, tumour lysis syndrome, hyperleukocytosis

Diagnostic Criteria:

• Peripheral blood or bone marrow with ≥20% blasts (WHO 2022/ICC 2022 classification) [4]
• Exception: Certain genetic abnormalities (e.g., t(15;17), t(8;21)) are diagnostic regardless of blast percentage
• Immunophenotyping and cytogenetic/molecular analysis essential for risk stratification

Outcomes:

• AML complete remission rates: 60-80% in younger patients, 40-60% in elderly
• ALL complete remission rates: > 90% in children, 80-90% in adults
• Long-term survival: AML 20-40% (age-dependent), ALL 85-90% (children), 40-50% (adults)
• Relapsed/refractory disease carries poor prognosis (median survival 3-6 months without salvage therapy)

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Epidemiology

Incidence and Prevalence

Acute Myeloid Leukaemia (AML):

• Annual incidence: 4.3 per 100,000 population in developed countries
• Age-adjusted incidence increases dramatically with age (> 20 per 100,000 in those > 75 years)
• Accounts for approximately 80% of all acute leukaemias in adults
• Median age at diagnosis: 68 years
• Rare in children (less than 10% of pediatric acute leukaemias)

Acute Lymphoblastic Leukaemia (ALL):

• Annual incidence: 1.7 per 100,000 population overall
• Bimodal age distribution: peak in early childhood (ages 2-5) and second peak after age 50
• Most common malignancy in children (25-30% of childhood cancers)
• Accounts for 20% of adult acute leukaemias
• Incidence ratio B-ALL:T-ALL approximately 4:1

Demographics

Risk Factors

Non-Modifiable:

• Age: AML incidence increases exponentially after age 40 [5]
• Genetic predisposition: Constitutional trisomy 21 (Down syndrome) confers 20-fold increased risk of ALL
• Inherited bone marrow failure syndromes: Fanconi anaemia, dyskeratosis congenita, Diamond-Blackfan anaemia
• Familial leukaemia syndromes: Li-Fraumeni syndrome (TP53 mutations), familial platelet disorder with propensity to AML (RUNX1 mutations)

Modifiable/Acquired:

Treatment-Related Acute Leukaemia: Therapy-related myeloid neoplasms (t-MN) account for 10-20% of all AML cases and are increasing in incidence due to improved survival from primary cancers. [8] These typically arise after exposure to:

• Alkylating agents (cyclophosphamide, melphalan): associated with del(5q), del(7q), complex karyotype
• Topoisomerase II inhibitors (doxorubicin, etoposide): associated with balanced translocations involving 11q23 (KMT2A)
• Radiation therapy: latency period 5-10 years

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Pathophysiology

Molecular Pathogenesis

Acute leukaemia arises from the stepwise accumulation of genetic and epigenetic alterations in haematopoietic stem and progenitor cells, resulting in dysregulated self-renewal, blocked differentiation, and clonal expansion. [9] Modern understanding emphasizes the "two-hit" hypothesis, requiring cooperating mutations in:

1. Class I mutations (proliferative advantage):

   • FLT3-ITD (internal tandem duplications): present in 25-30% of AML, associated with poor prognosis
   • RAS pathway mutations (NRAS, KRAS): 10-15% of AML
   • KIT mutations: particularly in t(8;21) and inv(16) AML

2. Class II mutations (impaired differentiation):

   • PML-RARA fusion (t(15;17)): pathognomonic for acute promyelocytic leukaemia (APL)
   • Core-binding factor rearrangements: RUNX1-RUNX1T1 (t(8;21)), CBFB-MYH11 (inv(16))
   • KMT2A (MLL) rearrangements: particularly common in therapy-related and infant ALL

3. Epigenetic modifiers:

   • DNMT3A, TET2, IDH1/IDH2: alter DNA methylation patterns
   • ASXL1, EZH2: chromatin remodeling alterations
   • Found in 40-50% of AML, often as early "founder" mutations in age-related clonal haematopoiesis

ALL-Specific Molecular Pathogenesis

B-cell ALL:

• Philadelphia chromosome (Ph+): BCR-ABL1 fusion from t(9;22), present in 25-30% of adult ALL, confers poor prognosis in pre-TKI era [10]
• High hyperdiploidy: > 50 chromosomes, favorable prognostic in pediatric ALL
• Hypodiploidy: less than 44 chromosomes, poor prognosis
• TCF3-PBX1: t(1;19), intermediate prognosis
• KMT2A rearrangements: infant ALL, poor prognosis

T-cell ALL:

• NOTCH1 mutations: present in > 50%, generally favorable prognostic impact
• CDKN2A/B deletions: tumor suppressor loss
• Aberrant expression of homeobox genes (TLX1, TLX3)

Clonal Evolution and Leukemic Stem Cells

Acute leukaemia exhibits hierarchical organization with leukaemic stem cells (LSCs) responsible for disease initiation, maintenance, and relapse. [11] LSCs are characterized by:

• Quiescence and relative chemotherapy resistance
• Self-renewal capacity
• Asymmetric cell division producing differentiation-arrested blasts
• Residence in protective bone marrow niches
• Minimal residual disease (MRD) positivity often reflects persistent LSCs

Bone Marrow Microenvironment

The bone marrow niche plays a crucial role in leukaemogenesis:

• Remodeling of oste

oblastic and vascular niches by leukaemic cells

• Suppression of normal haematopoiesis through direct cell-cell interactions and cytokine-mediated mechanisms
• Stromal cells provide survival signals and chemotherapy protection to LSCs
• Altered metabolic microenvironment (hypoxia, acidosis) selected for aggressive clones [12]

Consequences of Leukaemic Proliferation

Bone Marrow Failure:

• Anaemia: inadequate erythroid production → fatigue, dyspnea, pallor
• Neutropenia: increased infection risk (bacterial, fungal, viral)
• Thrombocytopenia: mucocutaneous bleeding, petechiae, severe hemorrhage risk

Organ Infiltration:

• Hepatosplenomegaly: common in ALL, less frequent in AML
• Lymphadenopathy: particularly T-ALL
• CNS involvement: 5-10% of ALL at diagnosis (prophylaxis required), rare in AML
• Testicular sanctuary site: relapse risk in male ALL
• Skin (leukaemia cutis), gums (myelomonocytic AML): specific AML subtypes

Metabolic Complications:

• Tumor lysis syndrome: spontaneous or treatment-induced cell death → hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia, acute kidney injury [13]
• Disseminated intravascular coagulation (DIC): particularly APL (t(15;17)), caused by procoagulant release from promyelocytes
• Hyperleukocytosis: WBC > 100 × 10⁹/L → hyperviscosity, leukostasis (pulmonary, CNS complications)

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Clinical Presentation

Symptoms: The Patient's Story

Timeline: Acute leukaemia typically presents subacutely over 2-12 weeks, though presentation can be more sudden with emergency complications.

Symptoms of Bone Marrow Failure (Most Common):

Symptoms of Organ Infiltration:

Emergency Presentations:

1. Neutropenic Sepsis:

   • Fever ≥38.3°C or ≥38.0°C sustained for > 1 hour
   • Neutrophil count less than 0.5 × 10⁹/L
   • May present with minimal inflammatory signs due to absent neutrophil response
   • Common organisms: Gram-negative bacteria (E. coli, Klebsiella, Pseudomonas), Gram-positive (Staphylococcus, Streptococcus)
   • Medical emergency requiring immediate broad-spectrum antibiotics

2. Severe Hemorrhage:

   • Platelet count typically less than 10-20 × 10⁹/L
   • Sites: intracranial, gastrointestinal, genitourinary, pulmonary
   • APL-associated DIC: life-threatening coagulopathy

3. Hyperleukocytosis (WBC > 100 × 10⁹/L):

   • Respiratory distress (pulmonary leukostasis)
   • Altered mental status, focal neurology (CNS leukostasis)
   • Occurs in 10-20% of AML, 10-30% of ALL [14]
   • Early mortality 20-40% if untreated

4. Tumor Lysis Syndrome:

   • Spontaneous (rare) or treatment-induced
   • Hyperkalemia (cardiac arrhythmias), hyperphosphatemia, hypocalcemia, hyperuricemia
   • Acute kidney injury from uric acid crystal deposition
   • Prevention essential in high-risk patients

Signs: Physical Examination Findings

General Appearance:

• Pallor (anaemia)
• Tachycardia, tachypnea (anaemia, sepsis)
• Febrile or hypothermic (infection)
• Cachexia (advanced disease)

Vital Signs:

Specific Examination Findings:

Red Flag Examination Findings:

[!CAUTION] Immediate Escalation Required:

• Septic shock signs (hypotension, altered consciousness, mottled skin) → immediate fluid resuscitation, broad-spectrum antibiotics, intensive care
• Active severe bleeding → platelet and coagulation factor support, identify bleeding source
• Respiratory distress with hyperleukocytosis → urgent cytoreduction (hydroxyurea, leukapheresis consideration)
• Papilledema or focal neurology → urgent imaging (intracranial hemorrhage vs. CNS leukemia)
• Superior vena cava syndrome → urgent steroids and/or radiotherapy (mediastinal mass)

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Investigations

Diagnostic Approach

The diagnosis of acute leukaemia requires integration of morphology, immunophenotyping, cytogenetics, and molecular genetics. Modern classification systems (WHO 2022, International Consensus Classification 2022) emphasize molecular characterization for risk stratification and treatment selection. [15]

First-Line Investigations

1. Complete Blood Count (FBC) with Differential:

2. Peripheral Blood Smear:

• Blast morphology: high nuclear-cytoplasmic ratio, open chromatin, nucleoli, cytoplasmic granules (AML) or scant cytoplasm (ALL)
• Auer rods (pathognomonic for AML, particularly APL)
• Dysplastic features in therapy-related or secondary AML

3. Bone Marrow Aspirate and Trephine Biopsy:

• Essential for diagnosis (except in rare cases of overwhelming peripheral blasts with diagnostic immunophenotype)
• Diagnostic criterion: ≥20% blasts of all nucleated cells (lower threshold for specific genetic abnormalities)
• Provides material for morphology, immunophenotyping, cytogenetics, molecular studies
• Trephine useful for assessing cellularity, fibrosis, spatial architecture

4. Immunophenotyping (Flow Cytometry):

Essential for lineage determination and subtype classification. [16]

AML Panel:

• Myeloid markers: CD13, CD33, CD117, MPO (cytoplasmic)
• Monocytic markers: CD14, CD64
• Megakaryocytic markers: CD41, CD61
• Stem cell markers: CD34, CD38
• Aberrant expression (useful for MRD monitoring): CD7, CD19

ALL Panel:

• B-cell markers: CD19, CD79a (cytoplasmic), CD10, CD20, surface/cytoplasmic immunoglobulin
• T-cell markers: CD3 (cytoplasmic/surface), CD5, CD7, CD4, CD8
• Precursor markers: CD34, TdT (terminal deoxynucleotidyl transferase)
• Aberrant markers for MRD

5. Cytogenetics (Karyotype):

Conventional chromosomal analysis remains the gold standard for detecting balanced translocations and complex karyotypes. [17]

AML Prognostic Stratification (ELN 2022):

ALL Cytogenetics:

6. Molecular Genetic Testing:

Increasingly routine for all acute leukaemia cases. [18]

AML Essential Molecular Panel:

• NPM1 mutations (30-35% of AML, favorable if FLT3-ITD absent/low)
• FLT3-ITD and FLT3-TKD (20-30%, adverse prognosis, targetable with midostaurin, gilteritinib)
• CEBPA mutations (biallelic = favorable)
• TP53 mutations (5-10%, very poor prognosis, resistance to standard therapy)
• IDH1/IDH2 mutations (10-20%, targetable with ivosidenib/enasidenib)
• RUNX1, ASXL1, EZH2 (adverse prognosis)

ALL Molecular Testing:

• BCR-ABL1 fusion (mandatory RT-PCR if Ph+ suspected by cytogenetics)
• BCR-ABL1-like (Ph-like) ALL (15-20% adult B-ALL, identifies kinase-activated subtypes amenable to targeted therapy)
• KMT2A rearrangements (infant ALL, therapy-related)
• iAMP21 (intrachromosomal amplification of chromosome 21)
• TCR/Ig gene rearrangements (clonality, MRD monitoring)

Baseline Assessment for Treatment Fitness

Biochemistry Panel:

• Renal function (urea, creatinine, eGFR): chemotherapy dosing, tumor lysis risk
• Hepatic function (ALT, AST, bilirubin, albumin): drug metabolism, prognosis
• Electrolytes: baseline for tumor lysis monitoring
• Uric acid: tumor lysis risk assessment
• LDH: tumor burden marker, tumor lysis risk
• Calcium, phosphate: tumor lysis monitoring

Coagulation Screen:

• PT/APTT, fibrinogen, D-dimer
• Essential in APL for DIC assessment
• Baseline before invasive procedures

Infection Screen:

• Blood cultures (if febrile)
• Viral serology: HIV, hepatitis B/C (reactivation risk with immunosuppression)
• Cytomegalovirus (CMV) serostatus
• Mycobacterium tuberculosis screening (IGRA/tuberculin test) if from endemic area

Tumor Lysis Syndrome Risk Stratification:

Cardiac Assessment:

• ECG: baseline before anthracycline chemotherapy
• Echocardiogram: baseline LVEF measurement (anthracyclines contraindicated if LVEF less than 50%)
• Troponin: if cardiac symptoms

Imaging:

• Chest X-ray: baseline, assess for infection, mediastinal mass (T-ALL)
• CT chest/abdomen/pelvis: if clinically indicated (lymphadenopathy assessment, infection source)
• Lumbar puncture with CSF analysis: ALL patients (diagnostic and CNS staging), AML if neurological symptoms
  • "Contraindications: thrombocytopenia less than 50 × 10⁹/L (relative), raised intracranial pressure"
  • CSF cell count, cytology, immunophenotyping
  • "CNS involvement (5-10% ALL, less than 5% AML): requires intrathecal chemotherapy"

HLA Typing:

• For all patients potentially eligible for allogeneic stem cell transplant
• Sibling and unrelated donor searches initiated early (during remission induction)

Minimal Residual Disease (MRD) Monitoring

MRD has emerged as the most powerful prognostic factor in acute leukaemia. [19] Techniques include:

Multiparameter Flow Cytometry (MFC):

• Sensitivity: 10⁻⁴ to 10⁻⁵ (1 leukaemic cell in 10,000-100,000 normal cells)
• Uses leukaemia-associated immunophenotypes identified at diagnosis
• Time points: post-induction, post-consolidation, pre-transplant

Molecular MRD (RT-qPCR):

• Targets leukaemia-specific fusion transcripts (PML-RARA, BCR-ABL1, KMT2A rearrangements) or TCR/Ig gene rearrangements
• Sensitivity: 10⁻⁴ to 10⁻⁶
• Standardized in APL (PML-RARA monitoring mandatory)

Next-Generation Sequencing (NGS):

• Emerging technique for personalized MRD monitoring
• Tracks patient-specific mutations
• Sensitivity comparable to MFC

Clinical Implications:

• MRD-positive status after induction/consolidation associated with increased relapse risk
• MRD-adapted therapy (treatment intensification for MRD+ patients) under investigation
• Pre-transplant MRD status predicts post-transplant outcomes

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Differential Diagnosis

The presentation of acute leukaemia overlaps with numerous haematological and non-haematological conditions. Key differentials include:

Haematological Disorders

Non-Haematological Conditions Mimicking Leukaemia

Differentiating AML from ALL

Critical for appropriate treatment selection:

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Management

The management of acute leukaemia has evolved substantially with the introduction of risk-adapted therapy, molecularly targeted agents, immunotherapy, and improved supportive care. [20] Treatment is typically divided into phases: remission induction, consolidation (intensification), and maintenance (ALL). Allogeneic stem cell transplantation plays a critical role in intermediate and high-risk patients.

Emergency and Supportive Care

Initial Stabilization:

1. Neutropenic Sepsis Management (if fever + neutropenia less than 0.5 × 10⁹/L):

   • Immediate broad-spectrum antibiotics within 1 hour of presentation (e.g., piperacillin-tazobactam OR meropenem)
   • Add vancomycin or linezolid if concern for MRSA or line-associated infection
   • Antifungal therapy (e.g., liposomal amphotericin B, caspofungin) if persistent fever > 96 hours
   • G-CSF (granulocyte colony-stimulating factor) in selected high-risk patients

2. Bleeding Management:

   • Platelet transfusion threshold: less than 10 × 10⁹/L prophylactically, less than 50 × 10⁹/L if active bleeding or pre-procedure
   • In APL with DIC: aggressive platelet and cryoprecipitate support (target platelets > 50, fibrinogen > 1.5 g/L)
   • Tranexamic acid for mucosal bleeding (avoid in DIC or hematuria)

3. Anemia Correction:

   • Transfuse packed red cells if Hb less than 70 g/L (symptomatic) or less than 80 g/L (cardiovascular comorbidity)
   • Irradiated blood products in allogeneic transplant candidates
   • CMV-negative products if CMV-seronegative transplant candidate

4. Tumor Lysis Syndrome Prevention/Treatment:

   • High-risk patients: rasburicase 0.2 mg/kg IV daily (recombinant urate oxidase)
   • Intermediate-risk: allopurinol 300-600 mg/day
   • Aggressive IV hydration (3 L/m²/day)
   • Electrolyte monitoring every 4-6 hours
   • Avoid potassium and phosphate in IV fluids
   • Hemodialysis if refractory hyperkalemia, symptomatic hypocalcemia, or acute kidney injury

5. Hyperleukocytosis Management (WBC > 100 × 10⁹/L):

   • Cytoreduction: hydroxyurea 2-4 g/day (rapidly reduces WBC)
   • Leukapheresis: consider if symptomatic leukostasis (controversial efficacy, used in select centers)
   • Avoid red cell transfusion (increases viscosity) until WBC reduced
   • Avoid prophylactic platelet transfusion in asymptomatic patients (theoretical risk of increased hyperviscosity)
   • Early initiation of chemotherapy once stable

6. APL-Specific Management:

   • Medical emergency: high early mortality from hemorrhage
   • Immediate ATRA (all-trans retinoic acid) 45 mg/m²/day in divided doses if APL suspected (do not await molecular confirmation)
   • Aggressive coagulation support: maintain platelets > 30-50 × 10⁹/L, fibrinogen > 1.5 g/L
   • Arsenic trioxide (ATO) 0.15 mg/kg/day (standard therapy in low/intermediate risk)
   • Monitor for differentiation syndrome (fever, dyspnea, hypoxia, weight gain, renal impairment): treat with dexamethasone 10 mg BD

Acute Myeloid Leukaemia (AML) Treatment

Treatment Algorithm (Age less than 60 Years, Fit for Intensive Chemotherapy):

DIAGNOSIS CONFIRMATION + RISK STRATIFICATION
                ↓
        INDUCTION CHEMOTHERAPY
    ("3+7" or alternative regimens)
                ↓
    ┌───────────────────────────────┐
    ↓                               ↓
Complete Remission (CR)         No CR (Refractory)
    ↓                               ↓
CONSOLIDATION THERAPY          SALVAGE CHEMOTHERAPY
    ├── Favorable risk: high-dose cytarabine × 3-4 cycles
    ├── Intermediate risk: consider allogeneic HSCT in CR1 if MRD+ or adverse molecular features
    └── Adverse risk: allogeneic HSCT in CR1

1. Induction Chemotherapy:

Standard "3+7" Regimen: [21]

• Daunorubicin 60-90 mg/m² IV days 1-3 (or idarubicin 12 mg/m² days 1-3)
• Cytarabine 100-200 mg/m² continuous IV infusion days 1-7
• Midostaurin 50 mg PO BD days 8-21 (if FLT3-mutated)
• CR rates: 60-80% (younger patients), 40-60% (age > 60 years)
• Median time to count recovery: 28-35 days
• Early mortality: 5-10% (younger), 10-30% (elderly)

Alternative Induction Regimens:

• FLAG-IDA: fludarabine + cytarabine + idarubicin + G-CSF (used in relapsed/refractory or high-risk disease)
• CPX-351 (liposomal daunorubicin/cytarabine): approved for therapy-related AML and AML with myelodysplasia-related changes; improves OS compared to standard 3+7 [22]
• Azacitidine + venetoclax: for patients unfit for intensive chemotherapy (age > 75 or comorbidities); CR rate 60-70%, median OS 14-18 months (superior to azacitidine alone)

2. Consolidation Therapy:

Post-Remission Strategy Based on Risk:

Allogeneic Stem Cell Transplantation:

• Curative intent in intermediate and adverse-risk AML [23]
• Timing: CR1 after 1-2 consolidation cycles
• Donor selection: HLA-matched sibling > matched unrelated donor (MUD) > haploidentical
• Conditioning regimens: myeloablative (age less than 50-55, fit patients) vs. reduced-intensity (older, comorbidities)
• Transplant-related mortality: 10-30% depending on age, donor type, conditioning intensity
• Graft-versus-leukaemia effect reduces relapse risk

3. Targeted Therapies in AML:

4. Elderly/Unfit AML Patients:

For patients unable to tolerate intensive chemotherapy (age > 75, poor performance status, significant comorbidities):

• Azacitidine 75 mg/m² SC/IV days 1-7, 28-day cycles (hypomethylating agent)
• Decitabine 20 mg/m² IV days 1-5, 28-day cycles
• Low-dose cytarabine (LDAC) 20 mg SC BD days 1-10
• Venetoclax + azacitidine (or LDAC): BCL-2 inhibitor; CR/CRi rate 60-70%, median OS 14-18 months (major advance in unfit AML) [25]

Acute Lymphoblastic Leukaemia (ALL) Treatment

Treatment Phases:

1. Remission induction (4-6 weeks)
2. Consolidation/intensification (6-9 months)
3. CNS prophylaxis/treatment (throughout)
4. Maintenance (2-3 years total therapy duration)

Treatment Algorithm:

DIAGNOSIS + RISK STRATIFICATION + Ph STATUS
                ↓
    ┌───────────────────────────────┐
    ↓                               ↓
Ph-Negative ALL                 Ph-Positive ALL
    ↓                               ↓
MULTI-AGENT INDUCTION           INDUCTION + TKI
(vincristine, steroids,         (dasatinib/ponatinib + steroids)
anthracycline, asparaginase)
    ↓                               ↓
CR rate > 90%                    CR rate > 95%
    ↓                               ↓
CONSOLIDATION +                 CONSOLIDATION + ONGOING TKI
CNS PROPHYLAXIS
    ↓                               ↓
Consider allogeneic HSCT        Allogeneic HSCT (if donor available)
if high-risk features           or TKI + chemotherapy maintenance
    ↓                               ↓
MAINTENANCE (2-3 years)         MAINTENANCE TKI indefinitely

1. Induction Therapy (Ph-Negative ALL):

Multidrug regimen adapted from pediatric protocols (e.g., UK ALL14, CALGB, Hyper-CVAD): [26]

Core Drugs:

• Vincristine 1.5-2 mg IV weekly × 4
• Dexamethasone 10 mg/m² PO daily days 1-28 (or prednisolone 60 mg/m²)
• Daunorubicin 45-60 mg/m² IV days 1, 8, 15, 22 (or doxorubicin)
• L-Asparaginase (PEG-asparaginase 2500 units/m² IM) or E. coli asparaginase
• Intrathecal chemotherapy (methotrexate ± cytarabine ± hydrocortisone) for CNS prophylaxis

CR Rate: 85-95% in adults Duration: 4-6 weeks Common toxicities: Neurotoxicity (vincristine), hyperglycemia (steroids), hepatotoxicity (asparaginase), pancreatitis (asparaginase)

2. Consolidation/Intensification:

Multiple cycles of high-dose chemotherapy to eliminate MRD:

• High-dose methotrexate (1-5 g/m²) with leucovorin rescue
• High-dose cytarabine
• Repeat induction-type drugs
• Continued intrathecal chemotherapy

3. CNS Prophylaxis:

Mandatory in ALL due to 30-50% CNS relapse risk without prophylaxis:

• Intrathecal chemotherapy (methotrexate, cytarabine, hydrocortisone) every 2-4 weeks during induction/consolidation
• High-dose systemic methotrexate and cytarabine (CNS penetration)
• Cranial irradiation (18-24 Gy) reserved for CNS-positive disease at diagnosis or high-risk T-ALL (neurotoxicity concerns)

4. Maintenance Therapy:

Continues for 2-3 years total duration from diagnosis:

• Mercaptopurine 75 mg/m² PO daily
• Methotrexate 20 mg/m² PO weekly
• Vincristine + steroid pulses monthly
• Monitor for cytopenias, hepatotoxicity
• Improves long-term survival in ALL (unlike AML where no role for maintenance)

5. Philadelphia Chromosome-Positive (Ph+) ALL:

BCR-ABL1 fusion present in 25-30% of adult ALL; historically dismal prognosis (median OS less than 12 months). Transformed by tyrosine kinase inhibitors (TKIs): [27]

Current Standard Treatment:

• Induction: TKI (dasatinib 140 mg/day OR ponatinib 45 mg/day) + corticosteroids ± vincristine
• Consolidation: Ongoing TKI + chemotherapy (reduced intensity compared to Ph-negative ALL)
• Allogeneic HSCT: Recommended in CR1 if donor available (improves OS)
• Maintenance: TKI continued indefinitely (even post-transplant)

TKI Selection:

• First-line: Dasatinib or ponatinib (ponatinib covers T315I mutation resistant to other TKIs)
• Second-generation TKIs (dasatinib, nilotinib) superior to imatinib in Ph+ ALL
• BCR-ABL1 mutation testing at relapse guides TKI selection

Outcomes with TKI-Based Therapy:

• CR rate > 95%
• 5-year OS: 50-70% (with allogeneic HSCT), 30-40% (chemotherapy + TKI alone)
• MRD monitoring essential (molecular remission predicts superior outcomes)

6. Novel Therapies in ALL:

7. Allogeneic Transplant Indications in ALL:

Relapsed/Refractory Acute Leukaemia

Definition:

• Primary refractory: failure to achieve CR after 1-2 induction cycles
• Relapsed: recurrence of disease after CR (morphological relapse: blasts > 5% in marrow, or extramedullary disease)

Prognosis:

• Relapsed/refractory AML: median OS 3-6 months without salvage therapy
• Relapsed ALL: 5-year OS less than 10% (adults) without allogeneic HSCT in CR2

Salvage Chemotherapy Options:

AML:

• FLAG-IDA (fludarabine, cytarabine, idarubicin, G-CSF)
• MEC (mitoxantrone, etoposide, cytarabine)
• HiDAC-based regimens
• Clinical trial enrollment strongly encouraged
• Venetoclax-based combinations in elderly

ALL:

• Hyper-CVAD or augmented BFM regimens
• Blinatumomab or inotuzumab ozogamicin (B-ALL)
• Nelarabine (T-ALL)
• CAR-T cell therapy (tisagenlecleucel for B-ALL)

Role of Allogeneic HSCT:

• Only potentially curative therapy for relapsed/refractory disease
• Requires achieving CR2 (second complete remission) with salvage therapy
• Donor availability crucial; haploidentical transplant option if no matched donor

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Prognosis and Outcomes

Prognostic Factors

AML:

ALL:

Outcomes by Subtype

AML (Overall):

• CR rate: 60-80% (younger), 40-60% (elderly)
• 5-year OS: 40-50% (younger), 10-20% (elderly)
• Relapse rate: 40-60% (chemotherapy alone), 20-40% (post-allogeneic HSCT)

ALL (Overall):

• CR rate: 90-95% (children), 80-90% (adults)
• 5-year OS: 85-90% (children), 40-50% (adults)
• Cure rates significantly lower in adults due to higher frequency of adverse features (Ph+, hypodiploidy, poor tolerance to intensive therapy)

APL (Acute Promyelocytic Leukaemia):

• Most curable AML subtype with ATRA + arsenic trioxide therapy
• CR rate: > 90%
• 5-year OS: 80-90%
• Early mortality (hemorrhage): 10-20% without prompt ATRA initiation

Long-Term Survivorship Issues

Survivors of acute leukaemia face multiple late effects requiring lifelong surveillance: [28]

1. Relapse:

• Risk greatest in first 2-3 years post-treatment
• Late relapses (> 5 years) occur but uncommon

2. Secondary Malignancies:

• Therapy-related MDS/AML (alkylating agents, topoisomerase II inhibitors)
• Solid tumors (radiation exposure, especially cranial irradiation in ALL)
• Cumulative incidence: 5-10% at 10-15 years

3. Cardiovascular:

• Anthracycline-related cardiomyopathy (dose-dependent; risk increases if cumulative daunorubicin > 300 mg/m²)
• Echocardiographic surveillance recommended
• Increased cardiovascular disease risk (especially post-transplant, metabolic syndrome)

4. Endocrine:

• Hypothyroidism (radiation, HSCT)
• Infertility (chemotherapy, total body irradiation)
• Growth hormone deficiency (cranial irradiation in ALL)
• Metabolic syndrome

5. Neurological:

• Cognitive impairment (methotrexate, cranial irradiation, intrathecal chemotherapy in ALL)
• Peripheral neuropathy (vincristine)
• Leukoencephalopathy (particularly methotrexate + cranial irradiation)

6. Psychological:

• Post-traumatic stress, anxiety, depression
• Reduced quality of life in subset of survivors

7. Infectious:

• Chronic viral infections (HBV, HCV reactivation)
• Lifelong risk if hypogammaglobulinemia (post-rituximab, HSCT with chronic GVHD)

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Special Scenarios

Acute Leukaemia in Pregnancy

Rare (1 in 75,000-100,000 pregnancies); presents unique ethical and clinical challenges. [29]

Principles:

• Multidisciplinary team: haematologist, maternal-fetal medicine specialist, neonatologist, ethicist
• Gestational age at diagnosis determines management approach

First Trimester (Weeks 0-13):

• Chemotherapy teratogenic (particularly methotrexate, cytarabine in weeks 4-8 organogenesis)
• Options:
  1. Delay treatment until second trimester (acceptable only if low tumor burden, no complications)
  2. Therapeutic termination + immediate chemotherapy (if mother desires)
  3. Proceed with chemotherapy (anthracyclines relatively safer) if life-threatening presentation

Second/Third Trimester (Weeks 14-40):

• Chemotherapy relatively safer (organogenesis complete)
• AML: standard induction chemotherapy (daunorubicin + cytarabine) can be administered
• ALL: avoid methotrexate (CNS toxicity risk); asparaginase caution (thrombosis risk increased in pregnancy)
• Avoid delivery during maternal nadir (weeks 2-3 post-chemotherapy) due to hemorrhage/infection risk
• Plan delivery at 32-34 weeks (ensure fetal lung maturity, minimize maternal/fetal chemotherapy exposure)

APL in Pregnancy:

• High mortality without treatment (hemorrhage)
• ATRA (all-trans retinoic acid): teratogenic in first trimester (craniofacial, cardiac, thymic abnormalities)
• Arsenic trioxide: avoid (limited data, theoretical teratogenicity)
• Second/third trimester: ATRA + anthracycline relatively safe

Outcomes:

• Maternal survival similar to non-pregnant patients if treatment not delayed
• Fetal outcomes: prematurity, intrauterine growth restriction, transient neonatal cytopenias

Acute Leukaemia in Older Adults (Age > 75 Years)

Represents majority of newly diagnosed AML cases but historically excluded from clinical trials. [30]

Challenges:

• Comorbidities (cardiac, renal, hepatic dysfunction)
• Performance status often poor (ECOG 2-4)
• Higher frequency of adverse cytogenetics and secondary AML
• Treatment-related mortality high with intensive chemotherapy (20-40%)
• Social factors (lack of caregivers, frailty)

Treatment Approach:

• Fitness assessment: Use of geriatric assessment tools, comorbidity indices (HCT-CI)
• Fit patients (ECOG 0-1, minimal comorbidities): Consider intensive chemotherapy (CPX-351 preferred over 3+7 in secondary AML)
• Unfit patients: Venetoclax + azacitidine (CR rate 60-70%, median OS 14-18 months; significant improvement over historical controls)
• Palliative/supportive care: Appropriate for very frail patients (ECOG 3-4, severe comorbidities)

Outcomes:

• Median OS with supportive care alone: 2-4 months
• Venetoclax + azacitidine: median OS 14-18 months
• Intensive chemotherapy (selected fit elderly): 5-year OS 10-20%

CNS Leukaemia

Epidemiology:

• Present at diagnosis: ALL 5-10%, AML less than 5%, higher in high WBC, monocytic AML, T-ALL
• Risk of CNS relapse without prophylaxis: ALL 30-50%, AML 5-10%

Diagnosis:

• Lumbar puncture with CSF analysis (cell count, cytology, flow cytometry)
• CNS involvement defined as: blasts on CSF cytospin OR cranial nerve palsies OR radiological CNS mass

Treatment:

• Intrathecal chemotherapy (methotrexate, cytarabine, hydrocortisone) 2-3 times weekly until CSF clear, then maintenance IT therapy
• Systemic high-dose methotrexate and cytarabine (CNS penetration)
• Cranial irradiation (18-24 Gy) for refractory CNS disease (neurotoxicity limits use)

Prognosis:

• CNS involvement at diagnosis: adverse prognostic factor
• CNS relapse: very poor prognosis (median OS 2-4 months without salvage therapy)

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Examination Viva Scenarios

Viva Scenario 1: Acute Promyelocytic Leukaemia (APL) Emergency

Clinical Stem: "A 42-year-old woman presents to the Emergency Department with a 2-week history of worsening bruising, gum bleeding, and epistaxis. On examination, she is alert, afebrile, with widespread petechiae and ecchymoses. Blood tests reveal: Hb 78 g/L, WBC 2.1 × 10⁹/L, platelets 18 × 10⁹/L, PT 18 seconds (control 12), APTT 42 seconds (control 30), fibrinogen 0.8 g/L (normal 2-4). Blood film shows abnormal promyelocytes with Auer rods."

Question: How would you manage this patient?

Model Answer:

This presentation is highly suspicious for acute promyelocytic leukaemia (APL) with disseminated intravascular coagulation (DIC)—a medical emergency requiring immediate intervention.

Immediate Management (First Hour):

1. Start ATRA immediately (do not await molecular confirmation):

   • APL is a medical emergency with high early mortality from hemorrhage
   • ATRA (all-trans retinoic acid) 45 mg/m²/day PO in divided doses
   • Initiation of ATRA reduces coagulopathy within 48-72 hours

2. Aggressive coagulation support:

   • Target: platelets > 30-50 × 10⁹/L, fibrinogen > 1.5 g/L
   • Platelet transfusion immediately
   • Cryoprecipitate for fibrinogen replacement
   • Fresh frozen plasma (FFP) to correct PT/APTT
   • Avoid heparin (contraindicated in active bleeding)

3. Avoid unnecessary procedures:

   • No lumbar puncture (high hemorrhage risk)
   • Central line insertion only if absolutely necessary (use ultrasound guidance, correct coagulopathy first)

4. Send confirmatory tests:

   • FISH or RT-PCR for PML-RARA fusion (diagnostic for APL)
   • Bone marrow aspirate (morphology, immunophenotype, cytogenetics) once stable

Subsequent Management (Days 1-7):

5. Risk-stratify APL (determines chemotherapy intensity):

   • Low-risk: WBC ≤10 × 10⁹/L, platelets > 40 × 10⁹/L
   • Intermediate-risk: WBC ≤10 × 10⁹/L, platelets ≤40 × 10⁹/L
   • High-risk: WBC > 10 × 10⁹/L

6. Add arsenic trioxide (ATO) and/or anthracycline:

   • Low/intermediate-risk APL (80% of cases): ATRA + ATO (arsenic trioxide 0.15 mg/kg/day IV) is standard (avoids chemotherapy, excellent outcomes)
   • High-risk APL: ATRA + ATO + idarubicin (chemotherapy added to reduce hyperleukocytosis risk)

7. Monitor for complications:

   • Differentiation syndrome: occurs in 10-25% (fever, dyspnea, hypoxia, pulmonary infiltrates, pleural/pericardial effusions, renal impairment, hypotension)
     • Treatment: dexamethasone 10 mg IV BD, consider ATRA interruption if severe
   • Tumor lysis syndrome: allopurinol prophylaxis, aggressive hydration
   • QTc prolongation: both ATRA and ATO can prolong QTc; monitor ECG, correct electrolytes (K, Mg)

Prognosis:

• With modern ATRA + ATO therapy: CR rate > 95%, 5-year OS 80-90% (most curable AML subtype)
• Early mortality: 10-20% (predominantly hemorrhage in first week before ATRA effect)
• Long-term outcomes: majority cured without need for allogeneic HSCT

Key Learning Points:

• APL is a medical emergency: start ATRA immediately on clinical suspicion
• Aggressive coagulation support essential in first 48-72 hours
• Differentiation syndrome is a life-threatening complication requiring steroids
• ATRA + ATO has transformed APL from fatal to highly curable

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Viva Scenario 2: Philadelphia Chromosome-Positive ALL in Young Adult

Clinical Stem: "A 28-year-old man presents with 4 weeks of fatigue, recurrent epistaxis, and night sweats. Examination reveals pallor, petechiae, and mild splenomegaly. Blood tests show: Hb 68 g/L, WBC 45 × 10⁹/L (70% blasts), platelets 22 × 10⁹/L. Bone marrow aspirate demonstrates 85% lymphoblasts. Immunophenotyping is consistent with B-cell ALL (CD19+, CD10+, TdT+, cCD79a+). Cytogenetics reveals t(9;22) BCR-ABL1 (Philadelphia chromosome-positive ALL)."

Question: Discuss the management and prognosis of this patient.

Model Answer:

This patient has Philadelphia chromosome-positive (Ph+) B-cell ALL, representing 25-30% of adult ALL. Ph+ ALL historically had dismal prognosis (median OS less than 12 months), but outcomes have been revolutionized by tyrosine kinase inhibitor (TKI) therapy.

Initial Management:

1. Risk stratification:

   • Ph+ ALL is universally considered high-risk disease
   • Requires intensive treatment including TKI and consideration for allogeneic HSCT

2. Supportive care:

   • Blood product support (RBC, platelets)
   • Tumor lysis syndrome prophylaxis (allopurinol, aggressive hydration; rasburicase if very high WBC)
   • CNS prophylaxis (intrathecal chemotherapy starting week 1-2)

Induction Therapy:

Modern approach uses TKI-based therapy with reduced-intensity chemotherapy:

3. TKI selection:

   • Dasatinib 140 mg/day PO (first-line in most protocols; CNS penetration superior to imatinib)
   • Ponatinib 45 mg/day PO (alternative; covers T315I resistance mutation)
   • Avoid imatinib (second-generation TKIs superior in Ph+ ALL)

4. Induction chemotherapy:

   • Corticosteroids (dexamethasone or prednisolone) + vincristine ± anthracycline
   • Reduced-intensity compared to Ph-negative ALL (TKI provides primary anti-leukaemic effect)
   • Avoid asparaginase (increases thrombosis risk with dasatinib)

5. Expected response:

   • CR rate > 95% with TKI-based induction
   • Molecular response (BCR-ABL1 transcript reduction) assessed by RT-qPCR at regular intervals

Post-Remission Therapy:

6. Consolidation:

   • Continue dasatinib throughout
   • Reduced-intensity chemotherapy cycles
   • Ongoing intrathecal chemotherapy (CNS prophylaxis)

7. Allogeneic stem cell transplantation:

   • Recommended in CR1 if HLA-matched donor available (sibling or unrelated donor)
   • Timing: after 2-3 consolidation cycles
   • Conditioning: myeloablative (if age less than 40, fit) or reduced-intensity (if older/comorbidities)
   • Outcomes: 5-year OS 50-70% post-HSCT (vs 30-40% with chemotherapy + TKI alone)
   • TKI continued post-transplant as maintenance (reduces relapse risk)

8. If no donor available or transplant-ineligible:

   • Continue chemotherapy + dasatinib through consolidation
   • Transition to maintenance therapy: dasatinib indefinitely + low-dose chemotherapy (vincristine/steroid pulses, methotrexate, mercaptopurine) for 2-3 years

Monitoring:

9. Minimal residual disease (MRD) monitoring:

   • BCR-ABL1 transcript levels by RT-qPCR every 3 months
   • Molecular response definitions:
     • Major molecular response (MMR): BCR-ABL1/ABL1 ratio ≤0.1% (3-log reduction)
     • Complete molecular response (CMR): undetectable BCR-ABL1 transcripts
   • MRD status strongest predictor of relapse risk

10. BCR-ABL1 mutation testing:

    • Performed if loss of response or rising MRD
    • T315I mutation: resistance to all TKIs except ponatinib
    • Guides TKI switch

Prognosis:

Key Prognostic Factors:

• Molecular response: Achievement of MMR/CMR by 3-6 months associated with excellent outcomes
• Allogeneic HSCT in CR1: Improves long-term survival
• TKI compliance: Non-adherence to TKI major cause of relapse

Relapsed/Refractory Ph+ ALL:

• BCR-ABL1 mutation testing mandatory
• Switch TKI based on mutation profile
• Blinatumomab or inotuzumab ozogamicin (if CD19+ or CD22+)
• CAR-T cell therapy (tisagenlecleucel) for multiply relapsed disease
• Allogeneic HSCT in CR2 if not performed in CR1

Key Learning Points:

• Ph+ ALL is high-risk but no longer uniformly fatal with TKI therapy
• Dasatinib or ponatinib preferred over imatinib
• Allogeneic HSCT in CR1 recommended if donor available
• MRD monitoring critical for early relapse detection
• Lifelong TKI maintenance improves outcomes

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Explaining to Patients and Families

What is Acute Leukaemia?

"Acute leukaemia is a type of blood cancer where your bone marrow—the spongy tissue inside your bones that makes blood cells—starts producing too many immature, abnormal white blood cells called 'blasts.' These blasts are faulty and don't work properly. They crowd out the normal blood cells, leading to three main problems:

1. Not enough red blood cells (anemia): This causes tiredness, breathlessness, and looking pale.
2. Not enough healthy white blood cells (neutropenia): This increases your risk of infections because your immune system isn't working properly.
3. Not enough platelets (thrombocytopenia): This causes easy bruising and bleeding because your blood doesn't clot properly.

There are two main types:

• Acute myeloid leukaemia (AML): More common in adults, especially older people.
• Acute lymphoblastic leukaemia (ALL): More common in children, but can affect adults.

Acute leukaemia develops quickly over weeks to months, which is why it's called 'acute.' Without treatment, it can be life-threatening within weeks to months. However, with modern treatment, many people can be cured or achieve long-term remission."

Why Did I Get Leukaemia?

"In most cases, we don't know exactly why someone develops acute leukaemia. It's not something you did wrong or could have prevented. It's not contagious—you can't catch it from someone else.

Some known risk factors include:

• Age: AML is more common as people get older.
• Previous chemotherapy or radiation: If you've been treated for another cancer in the past, there's a small increased risk.
• Genetic conditions: Certain inherited conditions (like Down syndrome) increase risk, but this is uncommon.
• Chemical exposure: Prolonged exposure to benzene or smoking increases risk slightly.

However, most people with acute leukaemia have no identifiable risk factors—it's often just bad luck."

How is Acute Leukaemia Treated?

"Treatment for acute leukaemia typically involves several phases and can last many months to years:

1. Chemotherapy (Main Treatment):

• You'll receive strong anti-cancer drugs through a drip into your vein (IV chemotherapy).
• The first phase is called induction chemotherapy—the goal is to kill the leukaemia cells and get your bone marrow back to normal. This usually takes 4-6 weeks.
• If induction is successful, you'll move to consolidation therapy—additional chemotherapy cycles to ensure all remaining leukaemia cells are destroyed. This can take 6-12 months.
• For ALL, you'll also have maintenance therapy—lower-dose chemotherapy tablets for 2-3 years to prevent relapse.

2. Targeted Therapy (If Applicable):

• Some leukaemias have specific genetic changes that can be targeted with special drugs (like TKIs for Philadelphia chromosome-positive ALL).
• These drugs specifically attack leukaemia cells while causing less harm to normal cells.

3. Stem Cell Transplant (For Some Patients):

• If your leukaemia is high-risk or comes back, you may need a stem cell transplant (also called bone marrow transplant).
• This involves receiving very high doses of chemotherapy to destroy all your bone marrow (including leukaemia), then receiving healthy stem cells from a donor to rebuild your blood system.
• This is a major treatment with significant risks, but can be curative.

4. Supportive Care:

• Blood transfusions to treat anaemia and low platelets.
• Antibiotics and antifungal medications to prevent and treat infections.
• Growth factor injections (G-CSF) to help your white blood cells recover faster.
• Management of side effects (nausea, pain, etc.).

5. Hospital Stays:

• You'll likely spend several weeks in hospital during induction chemotherapy (your blood counts will drop very low, increasing infection risk).
• Subsequent treatment cycles may be outpatient or involve shorter hospital stays."

What Are the Side Effects of Treatment?

"Chemotherapy is powerful but affects both leukaemia cells and normal fast-growing cells in your body. Common side effects include:

Short-Term (During Treatment):

• Hair loss: Temporary; hair regrows after treatment.
• Nausea and vomiting: Controlled with anti-sickness medications.
• Mouth sores: Painful ulcers; manage with mouth washes and pain relief.
• Infections: Very high risk when your white cell count is low; you'll need to stay away from crowds, people with infections, and report any fever immediately.
• Fatigue: Severe tiredness is common.
• Bleeding and bruising: Due to low platelets; avoid injuries.

Long-Term (After Treatment):

• Fertility: Chemotherapy can affect fertility; discuss sperm/egg preservation before starting treatment if this is important to you.
• Heart problems: Some chemotherapy drugs (anthracyclines) can weaken the heart; your heart function will be monitored.
• Risk of second cancers: Small increased risk of other cancers years later.
• Cognitive effects: Some people experience memory and concentration problems ('chemo brain').

Your medical team will monitor you closely and provide supportive care to minimize these side effects."

What Are My Chances of Being Cured?

"Your prognosis depends on many factors, including:

• Type of leukaemia: ALL generally has better outcomes in children than adults; AML outcomes depend heavily on genetic subtypes.
• Your age: Younger patients tend to tolerate treatment better and have better outcomes.
• Genetic features of your leukaemia: Some genetic changes indicate favorable prognosis (e.g., certain AML subtypes), while others are more challenging.
• How well you respond to treatment: Achieving remission quickly is a good sign.

Approximate Survival Rates:

• AML (adults): 40-50% long-term survival if younger and fit; 10-20% if elderly.
• ALL (adults): 40-50% long-term survival overall; higher in younger patients.
• ALL (children): 85-90% cure rate.

These are general statistics—your doctor will discuss your individual prognosis based on your specific situation. Many people achieve long-term remission or cure."

What Happens If the Leukaemia Comes Back (Relapse)?

"Relapse means the leukaemia has returned after treatment. If this happens:

• You'll receive different, more intensive chemotherapy (salvage therapy).
• The goal is to achieve a second remission, after which a stem cell transplant is usually recommended (this offers the best chance of cure for relapsed leukaemia).
• Newer treatments are also available, including targeted therapies and immunotherapies (like blinatumomab or CAR-T cell therapy for ALL).

Relapsed leukaemia is more challenging to treat than newly diagnosed leukaemia, but many people still achieve long-term remission with appropriate treatment."

How Can I Support Myself During Treatment?

"This is a very difficult time, but there are things you can do to help yourself:

Physical:

• Eat well: Maintain good nutrition (dietitian support available).
• Stay active: Gentle exercise when possible (walking, light stretching).
• Rest: Listen to your body; rest when fatigued.
• Infection prevention: Wash hands frequently, avoid crowds, report fever immediately.

Emotional:

• Talk to someone: Counseling, psychologist, or support groups for leukaemia patients.
• Stay connected: Friends and family can provide emotional support (phone/video calls if you can't see them in person due to infection risk).
• Ask questions: Your medical team is here to help—don't hesitate to ask about anything you don't understand.

Practical:

• Financial support: Social workers can help with financial concerns, disability benefits, travel assistance.
• Employer communication: Your team can provide letters explaining your situation to your employer.
• Advanced care planning: Some patients find it helpful to discuss their wishes for care if things don't go well (advance directives, power of attorney).

Support Organizations:

• Leukaemia Care, Blood Cancer UK, and other charities provide information, support groups, and practical help."

When Should I Seek Urgent Help?

Call 999 or go to the Emergency Department immediately if you experience:

• Fever ≥38°C (when your white cell count is low, this is a medical emergency requiring immediate antibiotics)
• Severe bleeding that won't stop
• Severe breathlessness
• Sudden severe headache or neurological symptoms (confusion, weakness, vision changes)
• Chest pain

Contact your haematology team urgently if you experience:

• Any fever (even less than 38°C)
• Signs of infection (cough, burning on urination, skin redness)
• Any bleeding or bruising
• Severe nausea/vomiting preventing you from keeping down fluids
• Severe pain

"Your team will give you emergency contact numbers—use them without hesitation. When your immune system is low, infections can become life-threatening within hours, so it's better to seek help early."

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Last Reviewed: 2026-01-06 | MedVellum Editorial Team

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Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists. This information is not a substitute for professional medical advice, diagnosis, or treatment.