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A 4-year-old girl presents with a 2-week history of increasing pallor, easy bruising, and intermittent leg pain. FBC: Hb 58 g/L, WCC 4.5 x 10^9/L with 30% lymphoblasts, platelets 28 x 10^9/L. Bone marrow aspirate confirms B-cell ALL with ETV6-RUNX1 fusion (t(12;21)).
Questions
a) What is the diagnosis and prognostic group? (3 marks)
B-cell acute lymphoblastic leukaemia (ALL) with ETV6-RUNX1 (TEL-AML1) fusion t(12;21). Favourable/standard risk: age 4 years (1-10), ETV6-RUNX1 is a GOOD prognostic feature. Expected 5-year event-free survival: over 90%.
b) What is the treatment protocol? (4 marks)
- Induction (4-6 weeks): dexamethasone, vincristine, asparaginase (E. coli or Erwinia), daunorubicin (reduced in standard risk)
- Consolidation: high-dose methotrexate, mercaptopurine
- CNS-directed therapy: intrathecal methotrexate at each phase (CNS is a sanctuary site)
- Maintenance: daily mercaptopurine + weekly methotrexate for 2-2.5 years (girls) or 3 years (boys)
- Response assessed by minimal residual disease (MRD) at day 29 — MRD-negative = excellent prognosis
c) What are the immediate complications to watch for? (3 marks)
- Tumour lysis syndrome: hyperkalaemia, hyperuricaemia, hyperphosphataemia, hypocalcaemia → AKI. Prevent: rasburicase + aggressive hydration
- Febrile neutropenia: urgent broad-spectrum IV antibiotics (piperacillin-tazobactam + gentamicin ± vancomycin)
- Bleeding: platelet support (maintain over 10, or over 20 if febrile/bleeding)
- Transfusion: packed RBC for anaemia (Hb under 70), irradiated/CMV-negative products
d) What is the prognosis? (1 mark)
ETV6-RUNX1 positive, standard-risk ALL: 5-year event-free survival over 90%. Cure rate is excellent with modern risk-stratified protocols. Long-term follow-up for late effects (cardiotoxicity from anthracyclines, growth, fertility, secondary malignancies).