Chronic myelodysplastic syndrome: short survival with or without evolution to acute leukaemia

The myelodysplastic syndromes represent a prognostically diverse group of disorders. Their study has recently been facilitated by the classification proposed by the French-American-British (FAB) Cooperative Group. Using this scheme it is now possible to define more precisely their natural history and clinical relationship to acute leukaemia. Using the longitudinal case control technique, we reviewed the clinical data and morphology of 69 patients (all elderly males) with chronic irreversible haematological cytopenia and dysplasia. Applying FAB criteria we found: refractory anaemia (RA) in 43%; sideroblastic anaemia (RA-S) in 33%; refractory anaemia with excess blasts (RAEB) in 13%; RAEB in transformation (RAEB-T) in 9% and chronic myelomonocytic leukaemia (CMML) in 1%. The median survival for the entire group was 27 months (RA, 52; RA-S, 29; RAEB, 12; RAEB-T 11; and CMML, 2 months). Short survival was predicted by transfusion requirement and other manifestations of severe cytopenia, as well as by myeloid immaturity. The presence or absence of sideroblastosis did not correlate with survival. Acute leukaemia developed in only eight patients (12%), six of whom initially had RA. Leukaemic transformation was not predicted by progressive cytological immaturity. This study demonstrates that even in the absence of leukaemic transformation, chronic myelodysplasia is a lethal haematological disorder.