Therapy-related myelodysplastic syndrome/acute myeloid leukemia M2 and translocation (8;21)

Therapy-Related Acute Myeloid Leukemia after Concurrent Chemoradiotherapy for Esophageal Cancer: Report of Two Cases

Concurrent chemoradiotherapy (CCRT) has become an important part of esophageal cancer treatment. Its efficacy has been proved and its acute adverse effects are well understood. Leukemogenesis is a potential late complication of ionizing irradiation and chemotherapy. Therapy-related acute myeloid leukemia (AML), however, has been rarely reported in esophageal cancer patients receiving CCRT. We here report two such cases. One patient received neoadjuvant CCRT and developed AML with a complex chromosome aberration 55 months after exposure to radiation- and cisplatin-based chemotherapy. The other had AML with t(8;21) twenty months following CCRT as definitive therapy. Such a severe complication of CCRT is a serious concern in esophageal cancer treatment. In the wake of the prolonged survival of some esophageal cancer patients, the treatment intensity may need to be reconsidered according to such experience.

Therapy-related acute myeloid leukemia with t(8;21) (q22;q22) shares many features with de novo acute myeloid leukemia with t(8;21)(q22;q22) but does not have a favorable outcome

To determine if therapy-related acute myeloid leukemia (t-AML) with t(8;21)(q22;q22) [t-AML-t(8;21)] harbors similar characteristic clinicopathologic features as de novo AML-t(8;21) (q22;q22), we studied 13 cases of t-AML-t(8;21) and 38 adult cases of de novo AML-t(8;21) diagnosed and treated at our hospital (1995-2008). Of 13 t-AML-t(8;21) cases, 11 had previously received chemotherapy with or without radiation for malignant neoplasms and 2 received radiation alone. The median latency to t-AML onset was 37 months (range, 11-126 months). Compared with patients with de novo AML-t(8;21), patients with t-AML-t(8;21) were older (P = .001) and had a lower WBC count (P = .039), substantial morphologic dysplasia, and comparable CD19/CD56 expression. The AML1-ETO (RUNX1-RUNX1T1) fusion was demonstrated in all 10 cases assessed. Class I mutations analyzed included FLT3 (0/10 [0%]), RAS (0/10 [0%]), JAK2 V617 (0/11 [0%]), and KIT (4/11 [36%]). With a median follow-up of 13 months, 10 patients with t-AML-t(8;21) died; the overall survival was significantly inferior to that of patients with de novo AML-t(8;21) (19 months vs not reached; P = .002). These findings suggest that t-AML-t(8;21) shares many features with de novo AML-t(8;21)(q22;q22), but affected patients have a worse outcome.

Can t(8;21) oligoblastic leukemia be called a myelodysplastic syndrome?

The new World Health Organization (WHO) classification of hematologic malignancies has incorporated t(8;21) myelodysplastic syndromes (MDS) according to the French-American-British classification into the category of acute myeloid leukemia (AML) with t(8;21)(q22;q22), while our knowledge about clinicopathological features of t(8;21) oligoblastic leukemia is still limited. We present our experience with 12 patients meeting the FAB diagnostic criteria of MDS and having t(8;21), who were compared to 43 t(8;21) AML patients. The MDS and AML patients shared most hematomorphologic, immunophenotypic, and clinical features, whereas the differences lay along myeloid maturation. The MDS patients had higher percentages of circulating neutrophils and marrow myeloid cells beyond promyelocytes than the AML patients. The incidence of Auer rods in mature neutrophils in MDS was significantly higher than that in AML, and furthermore, the neutrophils in MDS more commonly contain t(8;21) than in AML. Our findings support the rationale for the WHO classification, and future studies on large patient populations should help clarify whether the spontaneous differentiation potential could be actively associated with a hematological manifestation of t(8;21) leukemias.