This is an original JCO publication from 2001. Please visit the JCO website to access the full article.
Platelet Transfusion for Patients With Cancer
The Supportive Care Guideline Advisory Group is currently considering whether this guideline should be updated or archived.
Platelets for transfusion can be prepared either by separation of units of platelet concentrates (PCs) from whole blood, which are pooled before administration, or by apheresis from single donors. Comparative studies have shown that the posttransfusion increments, hemostatic benefit, and side effects are similar with either product. Thus, in routine circumstances, they can be used interchangeably. In most centers, pooled PCs are less costly. Single-donor platelets from selected donors are preferred when histocompatible platelet transfusions are needed. Both preparations can be stored for up to 5 days after collection at 20°C to 24°C with good maintenance of platelet viability.
Prophylactic Versus Therapeutic Platelet Transfusion
The Panel recommends that prophylactic platelet transfusion be administered to patients with thrombocytopenia resulting from impaired bone marrow function to reduce the risk of hemorrhage when the platelet count falls below a predefined threshold level. This threshold level for transfusion varies according to the patient’s diagnosis, clinical condition, and treatment modality.
Platelet Count Threshold for Prophylactic Platelet Transfusion: Acute Leukemia
The Panel recommends a threshold of 10,000/μL for prophylactic platelet transfusion in adult patients receiving therapy for acute leukemia, on the basis of the results of multiple randomized trials that demonstrate that this approach is equivalent to the use of a 20,000/μL threshold. Transfusion at higher levels may be necessary in newborns or in patients with signs of hemorrhage, high fever, hyperleukocytosis, rapid fall of platelet count, or coagulation abnormalities (for example, acute promyelocytic leukemia) and in those undergoing invasive procedures or in circumstances in which platelet transfusions may not be readily available in case of emergencies. The studies that form the basis of this recommendation (as well as the other recommendations in this section) have included adolescents but not younger children or infants. Nevertheless, it is probably reasonable to use similar guidelines for children and older infants. Although modern automated cell counters are quite accurate at low platelet counts, there can be modest variations in count because of limitations of the counting technology. The decision to transfuse at a precise trigger level should therefore consider the clinical context and the pattern of recent platelet counts.
Hematopoietic Cell Transplantation
Fewer studies have been performed in recipients of high-dose therapy with stem-cell support. Although such patients may experience more mucosal injury than patients receiving conventional antileukemic chemotherapy, clinical experience and the available data suggest that guidelines for prophylactic transfusion similar to those for patients with acute leukemia can be used in transplant recipients, with similar caveats about transfusion at higher counts in patients with complicating clinical conditions. The recent increased use of peripheral-blood stem cells with shorter durations of thrombocytopenia should further decrease the hemorrhagic risk.
Patients With Chronic, Stable, Severe Thrombocytopenia
No randomized studies have been performed in patients with sustained, severe thrombocytopenia such as can be seen in individuals with myelodysplasia and aplastic anemia. Many such patients have minimal or no significant bleeding for long periods of time despite low platelet counts. On the basis of clinical experience and limited retrospective studies, the Panel suggests that many of these patients can be observed without prophylactic transfusion, reserving platelet transfusions for episodes of hemorrhage or during times of active treatment.
Prophylactic Platelet Transfusion in Patients With Solid Tumors
The risk of bleeding in patients with solid tumors during chemotherapy-induced thrombocytopenia is related to the depth of the platelet nadir, although other factors contribute as well. Evidence obtained from observational studies supports the clinical benefit of prophylactic transfusion at a threshold of 10,000/μL platelets or less. The Panel suggests, however, on the basis of expert clinical opinion, that prophylactic transfusion at a threshold of 20,000/μL be considered for patients receiving aggressive therapy for bladder tumors as well as those with demonstrated necrotic tumors, owing to their presumed increased risk of bleeding at these sites.
Surgical or Invasive Procedures in Thrombocytopenic Patients
Thrombocytopenic patients frequently require invasive diagnostic or therapeutic procedures. Common procedures include placement of permanent or temporary central venous catheters, transbronchial and esophageal endoscopic biopsies, paranasal sinus aspirations, bone marrow biopsies, and occasionally even major surgery. The Panel suggests, on the basis of accumulated clinical experience, as attested to by a variety of consensus conference statements,55,56 that a platelet count of 40,000/μL to 50,000/μL is sufficient to perform major invasive procedures with safety, in the absence of associated coagulation abnormalities. Certain procedures, such as bone marrow aspirations and biopsies, clearly can be performed safely at counts of less than 20,000/μL. There are sparse data (summarized below) about the safety of other invasive procedures at much lower count levels. If platelet transfusions are administered before a procedure, it is critical that a posttransfusion platelet count be obtained to prove that the desired platelet count level has been reached. Platelet transfusions should also be available on short notice, in case intraoperative or postoperative bleeding occurs. For alloimmunized patients, histocompatible platelets must be available in these circumstances.
Prevention of Alloimmunization to RhD Antigens
Prevention of RhD alloimmunization resulting from RBCs contaminating platelet transfusions, either through the exclusive use of platelets from RhD negative donors or via anti-D immunoprophylaxis, should be considered for RhD-negative children (particularly girls) and for women of child-bearing age.
Prevention of Alloimmunization Using Leukoreduced Blood Products
The incidence of alloantibody mediated refractoriness to platelet transfusion can be decreased in patients with AML receiving induction chemotherapy when both platelet and RBC products are leukoreduced by filtration before transfusion (level I evidence). It is therefore appropriate to provide leukoreduced blood products to patients with AML from the time of diagnosis to ameliorate this important clinical problem. Although randomized trials have not been conducted in other patient groups, it is likely that alloimmunization can also be decreased in patients with other types of leukemia and in other cancer patients receiving chemotherapy. There are no data in patients who are not receiving chemotherapy in the same time periods that the transfusions are being administered (for example, aplastic anemia, myelodysplasia), although the consensus of opinion would favor its use in these patients as well. Because leukoreduction adds appreciably to the costs of transfusion, it should be used only for patients expected to require multiple platelet transfusions during their treatment courses and is not indicated for patients with cancer receiving RBCs or therapies that do not produce significant and sustained thrombocytopenia. In some countries, all blood products are now leukoreduced at the time of blood collection and component preparation. Should such prestorage leukoreduction become a routine in the United States, it would alleviate the need for additional filtration at the time of transfusion.
Diagnosis of Refractoriness to Platelet Transfusion
Although there are no empirical data to suggest that monitoring and acting on the postplatelet transfusion count decreases the incidence of hemorrhagic events, the Panel consensus is that posttransfusion platelet counts should be obtained after all transfusions, whenever possible. The Panel further recommends that additional transfusions be administered if the posttransfusion count is less than the platelet trigger appropriate for that clinical situation. Because patients may have a poor increment to a single transfusion yet have excellent platelet increments with subsequent transfusions, a diagnosis of refractoriness to platelet transfusion should only be made when at least two ABO-compatible transfusions, stored less than 72 hours, result in poor increments, as defined in the supporting text of the recommendation.
Management of Refractoriness to Platelet Transfusion
Patients with alloimmune refractory thrombocytopenia, as defined above, are best managed with platelet transfusions from donors who are HLA-A and HLA-B antigen selected. Most blood centers have access to computerized lists of such donors. For patients (a) whose HLA type cannot be determined, (b) who have uncommon HLA types for which suitable donors cannot be identified, or (c) who do not respond to HLA matched platelets, histocompatible platelet donors can often be identified using platelet cross-matching techniques. In many patients, these two techniques are complementary. There is no evidence that alloimmunized patients benefit from nonmatched prophylactic platelet transfusions that do not produce posttransfusion increments, and the Panel recommends that such patients be transfused only for hemorrhagic events.
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