Extramedullary infiltration at diagnosis and prognosis in children with acute myelogenous leukemia.
BACKGROUND
Extramedullary infiltration (EMI) is an occasional clinical symptom in childhood acute myelogenous leukemia (AML), but there is considerable controversy regarding the prognostic significance of EMI in AML.


METHODS
We evaluated the frequency and prognostic significance of EMI at diagnosis of AML in children.


RESULTS
Of 240 cases of de novo AML excluding children with Down syndrome and acute promyelocytic leukemia, 56 (23.3%) showed EMI at diagnosis. Patients with EMI had a higher initial WBC count and a higher proportion of M4/M5 morphological variants. The complete remission rate following induction chemotherapy was lower in patients with EMI. However, the overall survival and event-free survival did not differ between patients with and without EMI. A detailed analysis showed that patients with EMI with a WBC count at diagnosis of over 100 x 10(9)/L or infiltration into the central nervous system are likely to have a poor prognosis.


CONCLUSIONS
CNS leukemia and EMI together with a WBC count of >100 x 10(9)/L at diagnosis of AML are high risk factors for relapse, and alternative treatment approaches for patients with these characteristics should be explored.
Kobayashi
Ryoji
R
Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan. r-koba@med.hokudai.ac.jp
Tawa
Akio
A
Hanada
Ryoji
R
Horibe
Keizo
K
Tsuchida
Masahiro
M
Tsukimoto
Ichiro
I
D000208:Acute Disease; D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001842:Bone and Bones / Q000473:pathology; D002490:Central Nervous System / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003561:Cytarabine / Q000008:administration & dosage; D018572:Disease-Free Survival; D005047:Etoposide / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D005881:Gingiva / Q000473:pathology; D006801:Humans; D006854:Hydrocortisone / Q000008:administration & dosage; D015255:Idarubicin / Q000008:administration & dosage; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D007951:Leukemia, Myeloid / Q000175:diagnosis / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D017254:Leukemic Infiltration / Q000453:epidemiology*; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage; D009915:Orbit / Q000473:pathology; D011379:Prognosis; D012074:Remission Induction; D023981:Sarcoma, Myeloid / Q000188:drug therapy / Q000453:epidemiology* / Q000401:mortality; D012867:Skin / Q000473:pathology; D013737:Testis / Q000473:pathology
D003561:Cytarabine; D005047:Etoposide; D006854:Hydrocortisone; D008727:Methotrexate; D015255:Idarubicin