Prospective Randomized Clinical Feasibility Study of Red Cell Transfusion Goals in Patients with Acute Leukemias
Transfusion requirements and triggers have not been systematically studied in acute leukemia or other cancers. Acute leukemia carries a high mortality and any unnecessary increase in morbidity or mortality is not acceptable. Thus, without an obvious benefit gained from using higher transfusion thresholds, the added risks and costs of transfusion may be substantial and unnecessary. The investigators plan to study this issue in this pilot and feasibility study by randomly assigning patients treated for acute leukemia to be transfused with RBCs at either a higher or lower hemoglobin concentration trigger point. In this way, the investigators will be able to accurately determine if there is added benefit or harm to having a lower or higher red cell count during the induction treatment and recovery period for patients with acute leukemias. This safety data will serve as a platform for a larger mortality study in leukemia, and possibly additional studies in solid tumors.
1. Patients older than 18 years of age 2. Acute leukemia patients (AML, ALL, APL, tMN, high grade MDS) 3. Patients already being admitted to Johns Hopkins, Burke Services (WBG 5th floor) with plans for inpatient myelosuppressive chemotherapy
Nearly all patients with cancer experience some degree of anemia, either from the primary disease or from the treatment for their disease.13 Chemotherapeutic agents induce anemia by directly impairing hematopoiesis, including synthesis of RBC precursors in the bone marrow. In solid tumor oncology, traditionally there is not bone marrow involvement and these patients may only require a few units of RBCs during the course of their chemotherapy. In acute leukemia, primarily a cancer of the bone marrow, the space-occupying tumor cells prevent normal hematopoiesis in addition to this mechanism of treatment related anemia. The number of RBC units required to support a leukemia patient through their induction therapy may range from 30 â?? 60 units during the first 2 months of therapy. (Unpublished historical data from Johns Hopkins) These patients are universally supported with red cell transfusions. Depending on the type of RBC unit, transfused RBCs (approximately 300cc) can have a hematocrit ranging from 50-80% and typically contains 42.5 -80g of hemoglobin (Hb) with 147-278 mg of iron. The major benefit of RBC transfusion, not offered by other treatments, is a rapid increase in Hb and hematocrit levels. Hence, RBC transfusion is the only intervention for patients receiving myelosuppressive chemotherapy who require immediate correction of anemia. Transfusion of 1 unit of PRBC has been estimated to result in an average increase in Hb level of 1 g/dL or hematocrit by 3% in a normal-sized adult who is not experiencing a simultaneous loss of blood. Though required in our anemia patients, it must be realized that transfusions come with risks. While individually low, the combined toxicity of transfusions is significant.13 Multiple risks associated with transfusions include transfusion related acute lung injury (TRALI), hemolytic transfusion reactions, (HTR), viral and bacterial infections, transfusion associated circulatory overload (TACO), anaphylaxis, development of red blood cell antibodies, and iron overload. In a population such as ours that is committed to multiple transfusions over their treatment lifetimes, it seems prudent to assess if a minimization of these transfusions is possible. There is evidence that increased transfusions in cancer patients (all tumor types, predominantly solid tumors) are associated with increase in mortality (OR 1.34; 95% CI 1:29-1.38)8 This increased mortality may be related to more advanced disease versus the toxicities of transfusions such as increased infections. Cancer and chemotherapy induced anemia guidelines from the National Comprehensive Cancer Network (NCCN) are broad with large ranges for asymptomatic anemia of Hb 7-9g/dL and if symptomatic, then 8-10g/dL. It was suggested at the 2009 Transfusion Medicine State-of the-Science Symposium from the National Heart, Lung, and Blood Institute that RBC transfusion and/or blood conservation management RBC transfusion trigger strategies should be investigated to improve overall outcomes in different patient populations7 Acute leukemia patients represent a reasonable population in which to employ rigorous clinical trial procedures to address this issue. Much of our understanding of platelet transfusion management for oncology patients was studied in clinical trials involving patients with acute leukemia. 10, 12 Here we propose a pilot study using a restrictive strategy with patients receiving 2 units blood transfusion only when Hb is lower than 7 g/dL. Clinical outcomes, costs and quality of life will be compared. This initial effort will be a pilot study for the following: 1. Identify logistical issues related to protocol implementation. 2. Evaluate feasibility of recruitment rates, and how to perform data collection of clinical outcomes. 3. Define the sample size required for a definitive trial incorporating a mortality endpoint.
09/23/2014 04:03 AM