[A prospective study on course and prognostic criteria in "preleukemia" (author's transl)].

The natural course of disease was followed in 33 patients with so-called preleukemia by a prospective multicentric protocol. Patients with the following criteria were included: Anaemia with granulocytopenia and/or thrombocytopenia, normal or increased cellularity of the bone marrow and exclusion of a known diagnosis of underlying disease. Follow up after assumption of "preleukemia" was 3 years or more. Median survival was 26 months after diagnosis of preleukemia and 36 months after the first unequivocal symptoms of the blood dyscrasia. 40% of the patients changed to the picture of leukemia within 2 years. The most important parameters suggesting subsequent transition to overt leukemia where chromosomal abberations and an increased blast count of the bone marrow.