Therapy related AML in a case of chronic lymphocytic leukemia

In comparison to the general population, patients with chronic lymphocytic leukemia (CLL) are at a higher risk of developing secondary malignancies. Several factors may contribute to pathogenesis, including direct effects of chemotherapy and radiation as well as the reduction of immune surveillance. Factors influencing the increased risk include the increasing age of CLL patients, chronic antigenic stimulation, and immune impairment related to CLL or chemotherapy. Compared to patients with acute myeloid leukemia (AML) that developed from de novo, therapy-related AML (t-AML) has had a poorer outcome. The range of cytogenetic abnormalities in therapy-related AML is comparable to that in de novo AML, although these patients have a significantly higher frequency of unfavourable cytogenetics, such as a complex karyotype or a deletion or loss of chromosomes 5 and/or 7. Herein, we describe a case of therapy-related AML with monocytic differentiation and t(8;16) with a residual CLL population. The aim of the present case is to highlight rare occurrence of therapy related AML with t(8;16) in CLL after fluderabine based chemotherapy (FCR: fludarabine, cyclophosphamide, and rituximab). This case also highlights flowcytometric immunophenotyping as an ideal tool to characterize secondary AML along with the identification of minimal residual disease of CLL clone, which could have ignored at t-AML diagnosis. The pathogenesis of myeloid and lymphoid malignancies as well as their co-existence can be studied by focusing on such patients. Factors predisposing to the development of t-AML should be studied further, which would help in monitoring these patients more carefully.

The leukemia strikes back: a review of pathogenesis and treatment of secondary AML

Secondary AML is associated with a disproportionately poor prognosis, consistently shown to exhibit inferior response rates, event-free survival, and overall survival in comparison with de novo AML. Secondary AML may arise from the evolution of an antecedent hematologic disorder, or it may arise as a complication of prior cytotoxic chemotherapy or radiation therapy in the case of therapy-related AML. Because of the high frequency of poor-risk cytogenetics and high-risk molecular features, such as alterations in TP53, leukemic clones are often inherently chemoresistant. Standard of care induction had long remained conventional 7 + 3 until its reformulation as CPX-351, recently FDA approved specifically for secondary AML. However, recent data also suggests relatively favorable outcomes with regimens based on high-dose cytarabine or hypomethylating agents. With several investigational agents being studied, the therapeutic landscape becomes even more complex, and the treatment approach involves patient-specific, disease-specific, and therapy-specific considerations.

Pediatric acute myeloid leukemia as classified using 2008 WHO criteria: a single-center experience

The classification of acute myeloid leukemia (AML) has evolved to the most recent World Health Organization (WHO) schema, which integrates genetic, morphologic, and prognostic data into a single system. However, this system was devised using adult data and how this system applies to a pediatric cohort is unknown. Performing a retrospective chart review, we examined our single-center experience with AML in 115 children and classified their leukemia using the WHO 2008 schema. We examined patient samples for mutations of FLT3, NPM1, and CEBPA. Overall survival was calculated within categories. In our pediatric population, most cases of AML had recurrent genetic abnormalities of favorable prognosis. More than 10% of patients in our series were categorized as AML, with myelodysplasia-related changes, an entity not well-described in pediatric patients. In addition, a large proportion of patients were categorized with secondary, therapy-related AML. To our knowledge, this is the first application of the WHO 2008 classification to a pediatric cohort. In comparison to adult studies, AML in the pediatric population shows a distinct distribution within the WHO 2008 classification.