Impact Of Genetic Alterations And Types Of Chemotherapy On Outcomes Of Patients With Extramedullary Acute Myeloid Leukemia And Myeloid Sarcoma: A Single-Center Experience

Context: Extramedullary acute myeloid leukemia (eAML) and myeloid sarcoma (MS) is a very rare condition characterized by the proliferation of immature blasts in extramedullary sites. Nowadays, such relevant questions as the prognostic impact of genetic alterations among patients, choosing the optimal treatment strategy, the role of radiation therapy (RT), and allogeneic bone marrow transplantation (alloBMT) are discussed. Objective: To identify the prognostic importance of genetic aberrations and different types of therapy among patients with eAML. Patients: The study included 23 eAML/MS patients: 12 males and 11 females, with an age range of 13 to 78 years (median 38 years). They were classified according to the WHO criteria. All patients received chemotherapy with standard (“7+3”), high (“HiDAC”, “FLAG+/-Ida”), and low intensity, with or without RT. AlloBMT was performed in 17 patients (74%). Results: 20 patients (87%) had extramedullary lesions at the onset of the disease, and 3 patients had an extramedullary relapse of AML. Isolated MS was verified in 3 patients (17%). The most common sites were lymph nodes (21%), soft tissues (17%), bones (11%), and reproductive system (11%). 57% (13/23) of patients had multiorgan involvement. 17% (4/23), 26% (6/23), and 57% (13/23) of the patients were attributed to favorable, intermediate, and adverse risk categories, respectively. There were no significant correlations between ELN-2017 risk stratification and CR rates and frequency of early (during the first 12 months) relapse (p>0.05). Most of the patients with bone marrow involvement achieved CR (78%, 14/18), of whom 71% (10/14) achieved CR only after more than 2 cycles of chemotherapy, mostly because of persistent extramedullary disease (60%, 6/10). Using HiDAC in consolidation therapy significantly decreased the rate of early relapse (38% vs 100%, p=0.019). RT addition did not impact outcomes (p>0.05). The patients who received alloBMT at first CR had a lower risk of early relapse (12% vs 80%, p=0.015). Conclusion: The ELN-2017 stratification risk group does not influence the outcomes of patients with eAML/MS. Using HiDAC in consolidation therapy reduces the early relapse rate. The best time to perform the alloBMT among patients with eAML/MS is the first CR.