Extreme leucocytosis and prognosis of newly diagnosed patients with acute non-lymphocytic leukaemia.

A group of 87 consecutive patients with acute non-lymphocytic leukaemia (ANLL) who had been treated with large doses of hydroxyurea (HU) as a preliminary to protocol combination chemotherapy is reviewed. The outcome in patients whose initial leucocyte count was 100x10(9)/L or higher (HC group) is compared with that in the majority who had lower leucocyte counts. Contrary to reports in the literature, patients in the HC group had the same chance of achieving remission as the rest, and the survival of the responders was equally long in both groups. There were no deaths from intracerebral haemorrhage in the reportedly high-risk HC group, a fact which was attributed to the administration of HU to all new patients. Hydroxyurea rapidly lowered the leucocyte count in nearly all patients with ANLL and appeared to be a valuable addition to protocol therapy of this disease.