Stage Information
Newly Diagnosed
Remission
There is presently no therapeutically or prognostically meaningful staging
system for these disorders. Leukemia is always disseminated in the hematopoietic
system at diagnosis, even in children with acute myeloid leukemia (AML) who
present with isolated chloromas (also called granulocytic sarcomas). If these
children do not receive systemic chemotherapy, they invariably develop AML in
months or years. AML may invade nonhematopoietic tissue such as meninges,
brain parenchyma, testes or ovaries, or skin (leukemia cutis). Extramedullary
leukemia is more common in infants than in older children with AML.[1]
Newly Diagnosed
Childhood AML is diagnosed when bone marrow has greater than 20% blasts. The
blasts have the morphologic and histochemical characteristics of one of the French-American-British
subtypes of AML. It can also be diagnosed by biopsy of a chloroma. For
treatment purposes, children with a t(8;21) and less than 20% marrow blasts
should be considered to have AML rather than myelodysplastic syndrome.[2]
Remission
Remission is defined in the United States as peripheral blood counts (white blood cell
count, differential, and platelet count) rising toward normal, a mildly
hypocellular to normal cellular marrow with fewer than 5% blasts, and no
clinical signs or symptoms of the disease, including in the central nervous
system or at other extramedullary sites. Achieving a hypoplastic bone marrow
is usually the first step in obtaining remission in AML with the
exception of the M3 (acute promyelocytic leukemia [APL]); a hypoplastic marrow
phase is often not necessary prior to the achievement of remission in APL.
Additionally, early recovery marrows in any of the subtypes of AML may be
difficult to distinguish from persistent leukemia; correlation with blood
cell counts, clinical status, and cytogenetic/molecular testing is
imperative in passing final judgment on the results of early bone marrow
findings in AML.[3] If the findings are in doubt, the bone marrow
aspirate should be repeated in about 1 week.[1]
References
-
Ebb DH, Weinstein HJ: Diagnosis and treatment of childhood acute myelogenous leukemia. Pediatr Clin North Am 44 (4): 847-62, 1997.
[PUBMED Abstract]
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Chan GC, Wang WC, Raimondi SC, et al.: Myelodysplastic syndrome in children: differentiation from acute myeloid leukemia with a low blast count. Leukemia 11 (2): 206-11, 1997.
[PUBMED Abstract]
-
Konopleva M, Cheng SC, Cortes JE, et al.: Independent prognostic significance of day 21 cytogenetic findings in newly-diagnosed acute myeloid leukemia or refractory anemia with excess blasts. Haematologica 88 (7): 733-6, 2003.
[PUBMED Abstract]
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