Background: Since juvenile chronic myeloid leukemia (JCML) represents no more than 2% of leukemia in children, clinical and investigative experience of this disorder has been limited. In order to evaluate the diagnostic criteria currently applied, to provide centralized facilities for blood culture and to collect data on treatment, and to propose a uniform treatment protocol in our country, a National Registry for JCML was recently established in the "Associazione Italiana di Ematologia Oncologia Pediatrica" (AIEOP).
Patients: Out of the 24 cases reported from 9/35 centres, 22 were considered sufficiently documented and were enrolled in the Registry. Clonogenic assay on marrow and peripheral blood cells was performed in all available cases.
Results: Common features were non-specific clinical (fever, splenomegaly, hepatomegaly, lymphadenomegaly) and hematologic alterations (anemia, thrombocytopenia, leukocytosis usually < 50 x 10(9)/l, monocytosis, circulating immature granulocytes, increased HbF, normal karyotype). In 11 out of 11 cases, in vitro blood cultures showed the spontaneous growth of CFU-C in the absence of any exogenous source of colony-stimulating activity. Twelve of the 22 patients (55%) are alive (probability of survival 47.7%); most patients were treated according to an acute myeloid leukemia-directed schedule; 5/7 children treated with interferon were alive with disease after a median time of 29 months from diagnosis (range 8-95 months); 4/5 children who underwent bone marrow transplantation were alive in complete remission 10, 24, 42 and 118 months, after the diagnosis. Age < 1 year at presentation was the most significant prognostic factor in terms of probability of survival (80% vs 28%; p = 0.0024).
Conclusions: JCML must be considered in young children for whom acute leukemia has been suspected but ruled out; in vitro cultures should be considered mandatory to confirm the diagnosis. Age less than one year at the presentation was associated with prolonged survival. Only bone marrow transplantation was followed by prolonged disease-free survival, whereas intensive chemotherapy seemed not very effective and potentially associated with life-threatening complications. Interferon therapy appears to be a promising alternative to chemotherapy while the value of unrelated marrow donor is explored.