Platelet transfusion in thrombocytopenic cancer patients: Sometimes justified but likely insidious.

The transfusion of platelet concentrates prepared from allogeneic single or pooled donations is a standard procedure in transfusion medicine to stop or prevent bleeding in cancer patients with thrombocytopenia undergoing surgery, chemotherapy and/or radiotherapy. While platelet transfusion may appear reasonable in many instances, greater scientific and medical attention should however be given to the possibly insidious impact of transfused platelets on the outcome of cancers. Indeed platelets and the microvesicles they release possess all the biological ingredients capable of supporting tumor growth, protecting circulating tumor cells, and to contributing to metastatic invasion. Until any randomized controlled trials can objectively document their effects on survival or cancer recurrence, minimizing the use of platelet transfusion in cancer patients appears to represent a reasonable precautionary measure.

Transfusion-related immunomodulation and cancer.

Blood and blood-component therapy triggers immunological reactions in recipients. Transfusion-related immunomodulation [TRIM] is an important complex biological immune reaction to transfusion culminating in immunosuppression. The mechanisms underlying TRIM include the presence of residual leukocytes and apoptotic cells, the transfusion of immunosuppressive cytokines either present in donor components or generated during blood processing, the transfer of metabolically active growth factor-loaded microparticles and extracellular vesicles and the presence of free hemoglobin or extracellular vesicle-bound hemoglobin. TRIM variables include donor-specific factors as well as processing variables. TRIM may explain, at least in part, the controversial negative clinical outcomes observed in cancer patients receiving transfusion in the context of curative-intent surgeries. The use of novel technologies including metabolomics and proteomics on stored blood may pave the way for a deeper understanding of TRIM in general and its impact on cancer progression.

The microbiome and transfusion in cancer patients.

Our microbiota is determined by many variables including ABO blood groups. The microbiota is not only confined to the gut and skin but is also recoverable from blood of healthy donors. The microbiota shape our immune system through cross reactivity with antigens, the expression of direct molecular patterns, the release of cytokines, the effects on nutrients and micronutrients and even through an interplay with epigenetics. It is likely, therefore, that a donor's microbiota could alter the antigenicity of blood and its components and potentially contribute to transfusion-related immune modulation [TRIM]. It could also potentially transmit infections. The recipient's microbiome contributes, on the other hand, to the tolerance to transfused blood, or to the development of transfusion reactions. Cancer patients are a particularly vulnerable population, often immunosuppressed with a significantly altered microbiota. They are more at risk for transmission of "dormant" bacteria via blood transfusion. Furthermore, chemotherapy and radiation induce mucositis that likely results in significant translocation of gut microbiota and abnormal immune reactions to transfused blood. It is therefore relevant to revisit transfusion thresholds and consider transfusion-saving strategies in cancer patients.

Red blood cell transfusion and outcome in cancer.

Oncology services utilize about 15% of the blood transfusion resources in the USA. Red blood cell transfusion is performed immediately before, during or after major surgery to compensate for blood loss and hemodilution. However, a lack of evidence-based guidelines leads to variable transfusion practices among clinicians. The benefits of transfusing blood products are obvious in life-threatening low blood cell counts or bleeding, but it is becoming apparent that deliberate blood transfusion in some cancer patients can trigger negative clinical impacts. This review attempts to provide an overview of the impact of red blood cell transfusion in patients suffering from various types of oncologic pathologies.

Reflections on multiple strategies to reduce transfusion in cancer patients: A joint narrative.

Transfusion of red blood cells, platelets and plasma is widely used in the management of anemia and coagulopathy in cancer patients undergoing surgery, chemotherapy, and radiation. The decision to transfuse should not be made lightly as exposure to transfused blood, whether from an allogeneic or even autologous source, is not without risk and the long-term effect of blood transfusion on cancer outcomes remains questionable. Recognition of anemia associated with nutritional deficiency should be promptly corrected while avoiding the use of erythropoiesis stimulating agents. Minimizing blood loss and the prompt control of bleeding, coupled with a restrictive transfusion strategy, seem to be a reasonable approach that does not appear to be associated with long-term sequelae. Limiting platelet transfusion to patients with severe hypo-proliferative thrombocytopenia, and implementation of local hemostatic measures, together with the use of fractionated coagulation factor concentrates, as an alternative to frozen plasma transfusion, may reduce the exposure of cancer patients to potentially harmful thrombogenic and pro-inflammatory cellular microparticles. This joint narrative highlights current opinions for minimizing blood usage in patients with cancer.