Anemia is common in patients with malignant hematologic disorders and can be caused by a number of factors. Transfusion of red blood cells (RBCs) is often necessary for patients who are not responsive to transfusion-sparing strategies. Two critical questions must be addressed when considering transfusion for these patients: the first concerns quantity and includes issues of dosage, targets, and intervals; the second concerns quality and asks how to minimize the disadvantages arising from the complex nature of transfusion.
In a review paper, Christine Cserti-Gazdewich, MD, assistant professor in the department of medicine at the University of Toronto in Canada, discussed some of the challenges related to optimizing the quantity and quality of transfusion in individuals with hematologic malignancies.
“In the 2 dimensions that I explored — a series of quantitative and qualitative questions — I think the most important question to address is quantitative, as in how much is enough?” Dr Cserti-Gazdewich told Hematology Advisor.
She noted that when managing anemia, the goal is not to immediately rebuild normal RBC levels but instead to minimize morbidity and mortality with the lowest possible exposure.
“If it is possible to achieve the same alleviation of anemia with fewer [RBC] units and thus fewer visits and chair time for outpatients, this gain in quality of life is not paid for with more frequent returns, and the consumption of blood is truly reduced, then we will have achieved huge savings,” she said.
Getting Quantity Right
Conservative and liberal triggers must both be considered when determining transfusion quantity, Dr Cserti-Gazdewich wrote.
Initiating an RBC transfusion and deciding how much to give are “intertwined questions,” the answers to which depend on whether a conservative (in other words, restrictive) or liberal strategy is implemented. Current evidence and guidelines both endorse the use of clinically noninferior conservative RBC transfusion care strategies, such as triggering infusion when hemoglobin (Hb) is below 7 g/dL to 8 g/dL and administering single-unit doses to stable, nonbleeding inpatients. However, patients with hematologic malignancies are a unique subgroup and are often treated as outpatients, so they may be “left on the edges of these recommendations, with more questions than answers.”
Data from 23 randomized controlled trials with a combined cohort of 10,500 patients showed that 30-day mortality did not differ between patients treated with conservative (Hb threshold ≤ 7-8 g/dL) and liberal (Hb threshold ≤ 9-10 g/dL) approaches (9.0% vs 9.3%, respectively; relative risk, 0.97; 95% CI, 0.81-1.16). Outcomes for the 2 conservative Hb thresholds (14 trials at ≤ 8 g/dL and 9 trials at ≤ 7 g/dL) were also indistinguishable.
This collection of evidence suggests that the threshold at which to trigger transfusion is a well-studied matter, according to Dr Cserti-Gazdewich.
When looking specifically at transfusion in patients with hematologic malignancies, a Cochrane analysis of liberal compared with conservative RBC triggers in patients with myelodysplastic syndrome, aplastic anemia, and congenital bone marrow failure syndromes proved to be inconclusive. In another study, 300 patients undergoing either autologous (150 patients) or allogeneic (150 patients) stem cell transplantation were randomly assigned to Hb trigger thresholds of less than 7 g/dL or less than 9 g/dL for 100 days. The researchers found that conservative triggering was noninferior in the primary outcome of quality of life (P <.001) and that liberal use consumed more RBCs. There were no differences in other outcome measures.