Definition (Pediatr Clin North Am 1997;44:847)
• Clonal proliferation of any of the following (Parentheses denote French-American British Morphologic Classification): minimally differentiated myeloid cells (M0), myeloblasts (M1 and M2), promyelocytic (M3), myelomonocytic (M4), monocytic (M5), erythroleukemias (M6), or megakaryoblastic (M7)
• AML distinguished from myelodysplastic syndromes by >20% blasts in BM
Epidemiology (Pediatr Rev 2005;26:96; Pediatr Clin North Am 2008;55:21)
• ∼500 new pedi cases/yr in the United States; represents 4% of all childhood cancers
• Males = Females; equal incidence in black and white children
• More common than ALL in neonates; no age peak in childhood (median age = 65 yr)
Risk Factors (Pediatr Clin North Am 2008;55:21)
• Environmental: Exposure to chemo (alkylating agents, topo-2-isomerase inhibitors) or ionizing radiation, exposure to organic solvents, herbicides, pesticides
• Inherited: Down syndrome, Fanconi anemia, Kostmann syndrome, Shwachman–Diamond syndrome, Diamond–Blackfan syndrome, neurofibromatosis Type I, Klinefelter syndrome, Bloom syndrome, Li–Fraumeni syndrome
Clinical Presentation (Principles and Practice of Pediatric Oncology. 6th ed. Philadelphia, PA: LWW; 2011:566–587.)
• Fever (30%), bone pain (20%), lymphadenopathy (<20%), leukemia cutis (palpable, nontender nodules; may be colorless or blue) (<10%), gingival hypertrophy (<15%), granulocytic sarcomas/chloromas (solid tumors composed of AML blasts), bleeding (from thrombocytopenia or DIC, esp in APL), leukostasis
• CBC: Anemia (>50%), thrombocytopenia (75%), WBC >100,000 (20%)
• Blasts may be visible in peripheral blood smear
Prognosis (Pediatr Clin North Am 2008;55:21)
• Overall survival: ∼50%
• Favorable prognostic features: Age <50 yr, Down syndrome (special group w/ >80% cure rate) favorable cytogenetics: t(8;21), inv(16), t(15;17), possibly t(9;11)
• Unfavorable prognostic factors: Black race, WBC >100,000 at dx, monosomy 5 or 7, FLT3 gene mutations. Residual dz after induction either morphologically or by PCR/flow cytometry (minimal residual disease)
Treatment (Pediatr Clin North Am 2008;55:21)
• Generally shorter (<1 yr) and more intensive than ALL treatment
• Induction: Generally w/ cytarabine, anthracycline +/− etoposide given for at least 2 cycles along w/ intrathecal chemotherapy
• Consolidation: 3–4 cycles of high-dose chemotherapy featuring high-dose cytarabine
• AML protocols do not generally include maintenance phase w/ exception of APL Rx, which includes maintenance w/ all-trans retinoic acid (ATRA)
• Role of BMT: Major role in AML (most successful curative Rx after remission induced w/ chemo); ∼20% children have suitable HLA-identical sibling
• Whether SCT should be performed in 1st remission or reserved until 2nd is under study
• APL, Down syndrome, or children with t(8;21) or inv(16) should not be transplanted in 1st remission as they have favorable outcomes with chemo rx