AML transformation in 56 patients with Ph- MPD in two well defined populations.

The Philadelphia chromosome-negative (Ph-) chronic myeloproliferative disorders (MPD) have an inherent tendency for transformation into acute myelogenous leukaemia (AML). The long-term rate of leukaemic transformation in unselected MPD patients was studied in well-defined MPD populations in Gothenburg, Sweden and the Cote d'Or area, Burgundy, France, respectively. Over a median observation time of 15 yr, 56 subjects (7%) out of a total of 795 patients with Ph- MPD transformed to AML. The yearly incidence of AML transformation was 0.38% in polycythaemia vera (PV), 0.37% in essential thrombocythaemia (ET) and 1.09% in idiopathic myelofibrosis (IMF). The incidence of AML development was signif…