Extramedullary acute myeloid leukemia (eAML): Retrospective single center cohort study on clinico-pathological, molecular analysis and survival outcomes

Khalid Halahleh; Yazan Alhalaseh; Dalia Al-Rimawi; Waleed Da'na; Kamal Alrabi; Nazmi Kamal; Isra Muradi; Hikmat Abdel-Razeq

doi:10.1016/j.amsu.2021.102894

Extramedullary acute myeloid leukemia (eAML): Retrospective single center cohort study on clinico-pathological, molecular analysis and survival outcomes

Ann Med Surg (Lond). 2021 Oct 22:72:102894. doi: 10.1016/j.amsu.2021.102894. eCollection 2021 Dec.

Authors

Khalid Halahleh¹, Yazan Alhalaseh¹, Dalia Al-Rimawi², Waleed Da'na¹, Kamal Alrabi¹, Nazmi Kamal³, Isra Muradi⁴, Hikmat Abdel-Razeq¹

Affiliations

¹ Internal Medicine Department, King Hussein Cancer Center, Amman, Jordan.
² Research Office, King Hussein Cancer, Amman, Jordan.
³ Pathology Department, Hematopathology Section, King Hussein Cancer Center, Amman, Jordan.
⁴ Internal Medicine Department, University of Tripoli, Tripoli, Libya.

Abstract

Introduction: extramedullary acute myeloid leukemia (eAML) is characterized by extramedullary tumor formation infiltrated by myeloid blasts, with or without maturation and effaced architecture. The clinical, genetic and molecular aspects and overall outcomes are well defined worldwide, but not well characterized in our region.

Purpose and methods: This is a retrospective single center cohort study on 32 patients, who were identified over 10 years to study the clinical, pathologic and genetic-molecular aspects, and survival outcomes.

Results: eAML is rare (1%), occurs at a younger age with male predominance. Central nervous system (CNS) with facial bone invasion is most commonly identified (34.4%). 45.5% were positive for conventional myeloid markers (MPO), CD33, CD117, and 36% positive for CD34 and CD68. 54% with normal karyotype had deleterious mutations on further testing. NGS revealed pathogenic mutations in 76%(N-9/17) and none tested positive for P53, IDH1 or IDH2. At a median follow up time of 43mo (range, 8.6-80mo); 37.5%(N-12) were in complete remission, 62.5%(N-20) relapsed. 28% of relapses were after allotransplant. 31%(N-10) alive and continued in complete remission(CR), and 69%(N-22) of patients have died.Median overall survival (OS) is 18.4 and relapse free survival (RFS) 18.7 months. OS and RFS were significantly better in patients, who attained CR after induction (IC 11.9 mo vs zero; P = 0.0001; IC 12mo vs zero; P = 0.0001) compared to patients with relapsed disease; and in patients who received allo-transplant consolidation with median OS and RFS 42 vs 8.5mo (P = 0.002) and 42months vs 10 mo (P = 0.006). Thus allotransplant may be considered for all eligible patients in first CR.

Conclusion: achievement of complete remission after induction therapy is associated with improved outcomes in eAML. Allotransplant in first complete remission may be the most effective modality for achieving long-term remissions.

Keywords: AML; Extramedullary disease; Leukemia; Myeloid sarcoma.