The prognostic impact of extramedullary disease on the outcomes of AML patients undergoing allogenic-HCT

The impact of Extramedullary Disease (EMD) at diagnosis on the outcomes of Acute Myeloid Leukemia (AML) patients who underwent allogenic Hematopoietic Cell Transplantation (allo-HCT) at First Complete Remission (CR1) was retrospectively studied by Christianne Bourlon and colleagues from the Princess Margaret Cancer Center, Canada. The results of the study were published ahead of print in the European Journal of Haematology on 26^th May 2017.

In total, 303 AML patients (median age = 51 years) in CR1 who underwent allo-HCT between July 2000 and February 2014 at the Princess Margaret Cancer Center, University Health Network, Canada, were included in this study. Thirty-nine patients presented with concomitant EMD at diagnosis. The primary endpoint of the study was Overall Survival (OS). The secondary endpoints of the study were Cumulative Incidence of Relapse (CIR) and Non Relapse Mortality (NRM).

The key results of the study were:

• 3-year OS in patients with or without EMD; 55% vs 48%, P = 0.84
• 3-year CIR in patients with or without EMD; 18% vs 19%, P = 0.86
• 3-year NRM in patients with or without EMD; 26% vs 33%, P = 0.83

In summation, “EMD at diagnosis does not influence survival, disease relapse or non-relapse mortality post allo-HCT”. The authors concluded by stating that their findings indicate that “allo-HCT may overcome disease characteristics of AML, such as the presence of EMD, that otherwise would be considered high risk for disease relapse”.

Abstract

Objective

Extramedullary disease (EMD) at diagnosis of acute myeloid leukemia (AML) has been associated with increased risk of relapse and worse outcomes post-chemotherapy. The present study sought to investigate the association of EMD with outcomes following allogeneic hematopoietic cell transplantation (allo-HCT).

Method

This single-center retrospective study investigated the impact of EMD at diagnosis on the outcome of patients transplanted for AML in first complete remission (CR1). The study included 303 consecutive patients with AML transplanted in CR1, median age 51 years (range 18-71).

Results

EMD at diagnosis was documented in 39 patients (13%), either histologically (26 patients) or clinically/radiologically (13 patients). Among the 39 EMD patients, 16 had CNS disease, 7 had gingival infiltration and 5 had leukemia cutis. On univariate analysis, EMD had no significant impact on survival, with a 3-year OS of 55% (95% CI 38-69) compared to 48% for the non-EMD group (95% CI 42-55%) (p = .84). Likewise, 3-year CIR was 18% versus 19% (p = .86) and 3-year NRM was 26% versus 33% (p = .83) for EMD versus non-EMD groups respectively. Multivariate analysis confirmed these results.

Conclusion

We conclude that EMD at diagnosis of AML does not seem to influence outcomes following allo-HCT performed in CR1.