Issues for Blood Management in Hematology/Oncology
Hematology/Oncology patients comprise a unique subpopulation for whom transfusion therapy is often necessary in both the acute care setting as well as for long-term support. Red blood cells (RBCs) and platelets are the most common components transfused particularly in patients undergoing high-dose chemotherapy, intensive radiation therapy and human hematopoietic stem cell transplantation (HSCT).
Restrictive transfusion practice has become the “new world order” particularly for general medical and surgical patients. Those with hematologic malignancies or solid tumors have not frequently been a large part of many of the randomized controlled trials that speak to this approach. Literature is available, however, that provides evidence that judicious use of blood components via restrictive transfusion and single unit transfusions for inpatients and outpatients can be clinically effective, safe, and will decrease the potential for transfusion-associated adverse events.
Feasibility studies of restrictive RBC transfusion in the Hematology/Oncology population have been reported. These studies provide compelling evidence that lower transfusion triggers, targets and single unit use are not associated with increased bleeding episodes and will reduce overall transfusion exposure.¹ ² ³ The American Society of Hematology (ASH), as part of their Choosing Wisely Campaign, advises against liberal transfusion of RBCs with hemoglobin (Hgb) targets of 7- 8 g/dL, along with implementation of single-unit transfusions when possible.
Recent RCTs and consensus from the AABB point to similar restrictive practice for platelet transfusion with a trigger of 10,000/µL for prophylactic transfusion in most patients.⁵ Subgroups of patients, such as those with autologous HSCTs, may not require prophylactic transfusion at this level, but can be effectively transfused using a therapeutic-only strategy.⁶ The use of lower doses of platelets has been shown to be safe and effective.⁷ Similar strategies may also be applicable for outpatients.⁸
Pursuant to those patients receiving radiation therapy, historically, there have been reports in the literature that found loco-regional control to be improved in patients whose Hgb is maintained at a higher level, typically > 10 g/dL. Many, if not most of these studies had significant confounding and have not adjusted for comorbidities. A publication in 2012, however, concluded “…that hypoxia is a well-established cause of radio-resistance, but modification of this cannot be achieved by correcting low Hgb levels by…transfusion and/or [ESAs[.”⁹ Similarly, a recent study covering over 30 years of experience with cervical cancer patients undergoing radiation therapy (the original target population from a historical perspective) adjusted for confounders and found no evidence that anemia represented an independent predictor of outcomes associated with diagnosis or treatment. ¹° Transfusion, in and of itself, has significant negative immunomodulatory effects via cell-to-cell interactions and cytokines. Thus, maintenance of Hgb levels for these patients should not be considered an absolute necessity.
Other interventions may prove successful for Hematology/Oncology patients as part of a Blood Management Program. Identification and treatment of concomitant iron deficiency anemia or other nutritional deficiencies can potentially decrease or eliminate the need for transfusion. Drugs that might increase the risk for bleeding or hemolysis should be eliminated if possible as these cause or potentiate anemia. Use of new targeted drugs such as lenalidomide in patients with 5q deletion-associated MDS may prevent the need for long-term transfusion dependence. The use of antifibrinolytics in patients who have become refractory to platelet transfusions can enable platelet function even at low levels and prevent the unnecessary use of limited platelet resources.
Outpatient transfusion in the Hematology/Oncology arena comes with some unique circumstances. Many outpatients remain stable and will be capable of lower transfusion thresholds and longer intervals for both RBCs and platelets. Evidence-based restrictive transfusion can and should be a part of outpatient treatment strategy, just as with inpatients if the accessibility to post-transfusion care is adequate. No national guidelines are available for outpatient transfusion and each patient scenario must be considered on an individual basis, but certainly the absolute need for “standing” transfusions and obligatory 2-unit transfusions should be discouraged. Consider, as well, that patients often have their own view of the “need” for transfusion when symptoms and signs do not necessarily make it requisite. Discussion with our patients is essential to allow them to understand transfusion decisions.
The risks of transfusion are both immediate and delayed, particularly for those with chronic transfusion needs. Febrile non-hemolytic, allergic, hemolytic reactions, TRALI and TACO may occur as in other patient populations and should be recognized and treated as appropriate. Alloimmunization and transfusion-related iron overload are more common in the Hem/Onc arena given the potential for increased component exposure during the acute care setting and the high percentage of those that necessitate chronic transfusion support. The potential for transfusion-associated graft vs. host disease is also more worrisome given the degree of immunosuppression in these patients. Specialized products are often necessary including leukoreduced, antigen negative, irradiated or HLA-matched components. These specialized products may not be available on a STAT basis and add significantly to the overall transfusion cost. Careful consideration is warranted and inclusion of the Transfusion Service is key.
In the end, transfusion practice for Hematology/Oncology patients should include restrictive transfusion practices with assessment of the risks and benefits at the time of each potential transfusion episode. Each patient, whether inpatient or outpatient, should be evaluated based on their current state of stability, clinical course and availability and access to care. Nutritional assessments and subsequent interventions along with pharmaceutical agents may provide additional ways by which transfusion exposure can be decreased. Special products are often necessary and needs should be discussed with the Transfusion Service. Limiting transfusion ultimately avoids unpleasant, potentially severe acute and delayed adverse events as well as preserving resources within our communities.
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- Bishop et al. Int J Radiat Oncol Biol Phys 2014; doi: 10.1016/j.ijrobp.2014.09.023