Impact of Red Blood Cell (RBC) Transfusion During Induction Chemotherapy in Newly Diagnosed Patients with Acute Myeloid Leukemia (AML),
Authors: Komrokji Rami S. , Khan Awais M. , Ali Najla H Al , List Alan F. , Lancet Jeffrey E. 
Published: October 2019

Abstract
Abstract 3600

Background:
RBC transfusion dependency is a well known poor prognostic factor for patients with myelodysplastic syndromes, reflecting the underlying biology of disease and the impact of iron overload. To our knowledge, the impact of RBC transfusion (TX) on induction chemotherapy outcome in AML patients has not been investigated.

Methods:
Data were collected retrospectively in a cohort of newly diagnosed AML patients who received induction chemotherapy (3+ 7 regimen) at Moffitt Cancer Center. The primary objective of this study was to examine the relationship between number of RBC transfused units during first induction chemotherapy and outcome. Number of RBC units transfused only during the first cycle of induction were collected, and patients were divided into 2 groups, < 10 units RBC or ≥ 10 RBC units. All analyses were conducted using SPSS version 19.0. The Kaplan–Meier method was used to estimate median overall survival; chi-square test was used for comparison of categorical variables and t -test for continuous variables. Log rank test was used to compare Kaplan–Meier survival estimates between two groups and Cox regression for multivariable analysis.

Results:
135 AML patients who received 3+7 induction chemotherapy were included in this analysis. The median number of RBC units transfused during first induction chemotherapy was 10.0. Fifty nine patients received less than 10 units and 76 patients received 10 or more RBC units. Baseline characteristics were similar between patients with RBC units < 10 and those who received ≥ 10 units with respect to age, sex, history of antecedent MDS, karyotype, double induction requirement, and remission rates. (Table-1)
The median OS for patients who received < 10 units was 538 days (95%CI 199.3–876.7) compared to 296 days (95%CI 234–358) for patients who received ≥ 10 RBC (P=0.001). (Figure 1) The impact of RBC TX was greater in younger patients (< 60 years), for whom median OS was 798 days compared to 275 days in patients who had < 10 and ≥ 10 RBC units respectively, (p=0.013). In patients ≥ 60 years, the median OS was 275 days compared to 240 days for patients who had < 10 and ≥ 10 RBC units respectively, (p=0.06). Relapse rate was 52.5% (n=31) for patients who received < 10 units compared to 39.5% (n=30) in those who received ≥ 10 RBC units (p=0.09).
In a multivariable Cox regression analysis including age ≥ 60 years, karyotype, achieving remission (CR/CRi), receiving double induction, and RBC transfusion ≥ 10 units; age≥ 60 years [HR 1.5 (95%CI 1.0–2.2), p=0.047], karyotype [HR 1.7 (95%CI 1.3–2.3), P<0.005], and CR/CRi [HR 3.7 (95%CI 2.3–6.0), p<0.005], RBC≥ 10 units [Hazard ratio 1.8 (95%CI 1.2–2.7,p=0.006) were independent prognostic variables for OS.

Conclusion:
To our knowledge, this is the first study to identify a relationship between induction outcome and number of RBC units transfused (≥ 10 units) in AML patients. We hypothesize that requirement for RBC transfusion may reflect underlying disease biology, relative resistance to intensive chemotherapy or may lead to iron overload. These findings warrant confirmation in a larger, prospective study.

Disclosures:
No relevant conflicts of interest to declare.