Risk factors and clinical outcomes of acute myeloid leukaemia with central nervous system involvement in adults

Background: Acute myeloid leukaemia (AML) with central nervous system (CNS) involvement in adults is uncommon, and studies of this subject are scant. Methods: We conducted a retrospective study to investigate the clinical aspects, cytogenetic abnormalities, molecular gene mutations and outcomes of adult AML patients with CNS involvement. Three hundred and ninety-five patients with newly diagnosed AML were reviewed. Results: Twenty (5.1%) patients had CNS involvement, including 7 (1.8%) with initial CNS disease and 4 (1%) who suffered an isolated CNS relapse. The patients with CNS involvement were younger, had higher leukocyte, platelet, and peripheral blast cell counts, FAB M4 morphology, and chromosome translocations involving 11q23 (11q23 abnormalities) more frequently than did the patients without CNS involvement. No differences in sex, haemoglobin levels, serum LDH levels, immunophenotype of leukaemia cells, or molecular gene mutations were observed between the two groups. Multivariate analyses showed that age <= 45 years (OR, 5.933; 95% CI, 1.82 to 19.343), leukocyte counts >= 50,000/mu l (OR, 3.136; 95% CI, 1.083 to 9.078), and the presence of 11q23 abnormalities (OR, 5.548; 95% CI, 1.208 to 25.489) were significant predictors of CNS involvement. Patients with initial CNS disease had 5-year overall survival and relapse-free survival rates that were similar to those without initial CNS disease. However, three of four patients who suffered an isolated CNS relapse died, and their prognosis was as poor as that of patients who suffered a bone marrow relapse. Conclusion: CNS involvement in adult patients with AML is rare. Three significant risk factors for CNS involvement including age <= 45 years, leukocyte counts >= 50,000/mu l and the presence of 11q23 abnormalities were identified in this study. Future investigations to determine whether adult AML patients having these specific risk factors would benefit from CNS prophylactic therapy are necessary.