AML

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Definition: Acute Myeloid Leukemia. Rapidly progressive malignancy characterized by failure of myeloid cells to differentiate beyond blast stage.

Epidemiology:

- Older age (med age 65yo) - 10-15% of childhood leukemias

Risk Factors:

- Myelodysplastic syndromes (MDS) - Benzene - Radiation - Alkylating Agents as treatment for previous malignancy

Pathophysiology:

- Can be primary (de novo) or secondary (hematologic malignancies or previous chemotherapeutic agents) - Uncontrolled blast growth can lead to: 1) suppression of normal hematopoietic cells, 2) appearance of blasts in peripheral blood, 3) accumulation of blasts in other sites, 4) metabolic consequences such as tumour lysis syndrome

Clinical Features:

- Anemia - Thrombocytopenia (associated with DIC) - Neutropenia - Accumulation of blasts in marrow - Organ infiltration - Leukostasis/hyperleukosis syndrome (medical emergency)

Investigations:

1) Bloodwork: CBC (anemias, thrombocytopenias, variable WBCs); INR, aPTT, FDP, fibrinogen (in case of DIC); increased LDH, increased uric acid, increased phosphate, decreased calcium; baseline renal and function tests 2) Peripheral blood film: circulating blasts with Auer rods are pathognomonic for AML 3) Bone marrow aspirate: blast count >20% (normal is 4) CXR to R/O pneumonia, ECG, MUGA scan prior to chemotherapy (cardiotoxic)

Treatment:

Pneumonic: ICS 1) Induction chemotherapy (to induce complete remission of AML) 2) Consolidation (to prevent recurrence). Can be chemotherapy or stem cell transplantation. 3) Supportive care: screen for infection, fever, platelets and RBC transfusions, prevention and treatment of metabolic abnormalities, consider G-CSF for severe infections

Prognosis:

Median survival: 12-24mo 5 year survival: 40%

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