The Influence of the Duration of Storage of Red Blood Cells On Cancer Survival
Authors: Kekre Natasha , Mallick Ranjeeta , Allan David S. , Tinmouth Alan , Tay Jason 
Published: October 2019

Abstract
Abstract 1184

Background:
The duration of storage of red blood cells (RBC) has been associated with poor clinical outcomes amongst those receiving red cells. Patients with cancer are at risk of RBC transfusions and the effect of RBC storage is unknown in this population. We investigated the influence of duration of storage of RBC units transfused on overall survival (OS) and cancer recurrence in patients diagnosed with a new malignancy. We further described the transfusion requirements in this cohort of patients.

Methods:
Patients diagnosed with cancer at The Ottawa Regional Cancer Centre between January 01, 2000 and December 31, 2005 were included. Data was retrieved from the Ottawa Hospital Transfusion and Cancer database for analysis. RBC units were categorized as “new” if stored for less than 14 days, “intermediate” if stored between 14 to 28 days and “old” if stored for more than 28 days. Baseline characteristics between the comparative groups were compared by ANOVA test. Categorical variables and continuous variables were compared using Chi-squared and Wilcoxan rank-sum tests respectively. Kaplan-Meier analyses were used to examine differences in unadjusted survival while Cox-regression analyses were applied to adjust for potential confounding variables.

Results:
There were n=27,591 patients diagnosed with any cancer. The mean number of packed RBC units transfused was 3.42 (0.22, 6.62) with 1,929 (7.0%) patients receiving RBC within 1 year of diagnosis. Of these patients, 1335 (69.2%) received exclusively one “aged” category of RBC. The median OS was worse for patients who were transfused versus those not transfused (1.1 vs 7.5 years respectively, p<0.0001) as well as the number of RBC transfused (median OS for 1–2 units was 1.2 years, 3–5 units was 1.05 years and 6 or more units was 1.1 years; p=0.0017) in univariate analysis. Overall survival was not associated with duration of storage of transfused RBC with a median survival of 1.2, 1.7, 1.1 years for only new, intermediate and old RBC units respectively (p=0.36). Cancer recurrence was significantly higher in patients who received a RBC transfusion than those who did not (56.3% vs 33.0% respectively; p<0.0001) but was not affected by the duration of storage of transfused RBC (p=0.06). In multivariate analysis, a diagnosis of lung cancer, chemotherapy use, radiation use, cancer-related surgery and cancer recurrence were associated with inferior overall survival (p<0.05). In contrast, neither the number of RBC units transfused nor the duration of RBC storage before transfusion were associated with OS in multivariate analysis.

Conclusion:
In patients diagnosed with cancer, the duration of storage of transfused RBC had no impact on OS or cancer recurrence. However, the number of RBC transfused was associated with an increased risk for cancer recurrence. This suggests that current RBC storage policies are adequate for patients with malignancy requiring RBC transfusions.

Disclosures:
No relevant conflicts of interest to declare.