Preleukemic changes in cases of nonlymphocytic leukemia secondary to cytotoxic therapy. Analysis of 105 cases

Peripheral blood changes preceding therapy-related leukemia were studied in 105 patients who had received cytotoxic therapy, 53 for Hodgkin's disease and 52 for other cancers. Preleukemic anomalies were observed in 74.3% of the cases, appearing after a mean interval of 68.7 months after diagnosis of the initial cancer. This interval was only 57.5 months in patients aged 50 years or older and only 42.3 months in patients with Hodgkin's disease having received cytotoxic therapy for 6 months or less. The first changes most frequently observed were pancytopenia (24.8%) and isolated erythrocyte abnormalities such as anemia or macrocytosis (18.1%). Involvement of two cell lines, isolated thrombocytopenia or leukopenia, circulating immature cells, monocytosis, leukocytosis, or thrombocytosis were also observed. Therapy-related myelodysplastic syndrome was recognized in 19 patients and myelofibrosis in 3. Median duration of the preleukemic phase was 6 months; 9 months in cases of isolated erythrocyte involvement and 5 months in the other cases. Myelomonocytic or monoblastic leukemia appeared less frequently when the first sign involved erythrocytes only. Hematological surveillance thus appears necessary in all patients having received cytotoxic therapy. Bone marrow study with cytogenetic examination should be performed in cases of persistent peripheral blood abnormalities.