In the 2008 World Health Organization classification, cases of acute myeloid leukemia (AML) and myelodysplastic syndrome that arise after chemotherapy or radiation therapy for a primary neoplasm are considered together as therapy-related myeloid neoplasms (TR-MNs). This concept, however, is not universally accepted since there are confounding variables in attributing myeloid neoplasms to earlier therapies.
Cases in session 6 of the 2013 Workshop of the Society for Hematopathology/European Association for Haematopathology illustrated myeloid neoplasms thought likely to be TR-MNs, and discussed the differences and biologic similarities with de novo myeloid neoplasms.
We reviewed data showing that diagnosis of TR-MN alters patient outcome only in specific subsets. The session also included examples of therapy-related AML with recurrent genetic abnormalities, such as t(15;17), inv(16), and t(8;21), and reports were highlighted showing that patients with these neoplasms have clinical outcomes similar to patients with their de novo counterparts.
The study of TR-MNs will likely provide insight into the pathogenesis of de novo myeloid disease and may explain why some patients with cancer develop TR-MN and evidently have a higher genetic susceptibility, whereas most patients treated with the same agents do not. These studies will also result in critical reappraisal of current concepts related to TR-MNs.