Incidence and treatment of potentially lethal diseases in transient leukemia of Down syndrome: Pediatric Oncology Group Study.

Transient leukemia (TL or transient myeloproliferative disorder) occurs in approximately 10% of newborn infants with Down syndrome. The disorder is characterized by the presence of megakaryoblasts in the peripheral blood; most cases resolve spontaneously within the first 3 months of life, and the child is well thereafter. However, there are cases in which a severe, potentially lethal form of disease develops, manifesting as hepatic fibrosis or cardiopulmonary failure. Hitherto, the incidence of these severe forms of the disease has not been reported. A prospective study of TL was conducted by the Pediatric Oncology Group (POG Study 9481) in which 48 children with TL were identified. Life-threatening disease occurred in nine patients (19%); seven had hepatic fibrosis and two had cardiopulmonary failure. Five children died of the disease within the first 3 months of life, none of whom received antileukemic therapy. One patient died on day 31 after receiving minimal therapy within 1 day of death. Three children received low-dose cytosine arabinoside (Ara-C) (0.4-1.5 mg/kg every 12 hours for 5 or 7 days). In all these patients, the disease resolved. It is concluded that potentially lethal disease is relatively common in TL, and the available evidence suggests that these diseases are responsive to low-dose Ara-C therapy.