Chronic myelomonocytic leukemia: single entity or heterogeneous disorder? A prospective multicenter study of 100 patients. Groupe Français de Cytogénétique Hématologique.

To investigate the prognostic factors in chronic myelomonocytic leukemia (CMMoL), and to determine the importance of cytogenetic abnormalities at diagnosis and during evolution, a multicentric prospective study was established by the Groupe Français de Cytogénétique Hématologique. One hundred patients were analyzed: 29 had cytogenetic abnormalities, among which the most frequent were +8, -Y, -7/7q-, and 12p-. Transformation into acute leukemia (AL) occurred in 26 patients. At transformation, eight patients had new cytogenetic abnormalities, not different from those described in the chronic phase of this disease. The median survival was 36 months (+/- 20 months, 95%, confidence interval). In multivariate analysis, four factors were associated with shorter survival: anemia less than 10 g/dl, thrombocytopenia less than 100 x 10(9)/L, splenomegaly, and the presence of immature precursors (IMP) in peripheral blood (PB). A very good prognosis subgroup could be identified which included eight patients with myelodysplasia and monocytosis only and none of the four unfavorable prognostic factors. This study confirmed the cytogenetic findings previously described by our group, and its results yielded further prognostic information. It also indicates the heterogeneity of this disease [some patients show clinical and biologic features of myeloproliferative syndromes (MDS, especially karyotypic abnormalities described only in these syndromes), whereas others appear more to have myelodysplasia, shifting from refractory anemia (RA) to CMMoL], and stresses the need for a more precise definition of this entity.