IntroductionCentral nervous system involvement (CNS) at first relapse can be a serious complication during the clinical course of patients with acute myeloid leukemia (AML).1 To our knowledge, this complication has been critically assessed in patients with acute promyelocytic leukemia (APL) 2 and children with acute myeloid leukemia.3 However, the prevalence of and risk factors for central system involvement in adult patients with acute myeloid leukemia have been analyzed in only a few studies carried out in the 1980s 4-8 and 1990s. 9,10 No studies to date have analyzed the incidence of and risk factors for central nervous system relapse using the most appropriate statistical methods, i.e. cumulative incidence (CI) and multivariate analysis. Therefore, there is a lack of reliable information about central nervous system relapse in adult patients with acute myeloid leukemia, particularly in those treated with modern chemotherapy protocols.In this study, we assessed the cumulative incidence and outcome of and risk factors for central nervous system involvement at first relapse in a large cohort of adult patients diagnosed with non-promyelocytic acute myeloid leukemia who were treated with intensive chemotherapy protocols during the past three decades at a single institution.
Design and MethodsThis study included all adult patients over 13 years of age who were diagnosed consecutively with acute myeloid leukemia in a single institution (Hospital Universitari i Politècnic La Fe, València, Spain) between 1979 and 2009, and who achieved complete remission (CR) after intensive induction chemotherapy. The diagnosis and classification of AML were made according to the FrenchAmerican-British (FAB) criteria, 11,12 and were based on the World Health Organization 2002 criteria. 13 Patients with acute promyelocytic leukemia were excluded from the study. The study was approved by the Research Ethics Board, and all patients provided informed consent according to institutional guidelines.The chemotherapy schedules used in the first patients from 1979 to 1985 (group 1; n=56) included adriamycin (cumulative doses [CD] of 180 mg/m 2 ), cytarabine (CD 3,150 mg/m 2 ), and 6-thioguanine or vincristine as the induction and consolidation therapy, which was followed by maintenance with polychemotherapy for 1-2 years. From 1986 to 1990 (group 2; n=73), therapy comprised induction and consolidation with the combination of cytarabine (CD 2,800 mg/m