Do all patients with haematological malignancies need prophylactic platelets? No

Abstract

Nearly, all patients, whether receiving treatment with autologous hematopoietic stem cell transplantation (autoHSCT), intensive chemotherapy or allogeneic HSCT (alloHSCT), will receive one or more transfusions of platelets, most as prophylaxis. Optimal use of prophylactic platelet transfusions for prevention of haemorrhage in all patients with treatment‐induced myelosuppression remains controversial. Two randomized controlled trials of prophylactic platelet transfusions have recently been completed in adults with thrombocytopenia due to haematological malignancies or their treatment. Both found a no‐prophylaxis approach led to higher rates of World Health Organization (WHO) grade 2–4 bleeding overall. A key question is whether all subgroups of patients benefited equally from prophylactic platelet transfusions. Prespecified subgroup analysis in the Trial of Prophylactic Platelets (TOPPS) study found that the reduction in proportion of patients experiencing WHO grade 2–4 bleeds (main trial outcome) seen in the prophylaxis arm was of greater magnitude in chemotherapy/allogeneic hematopoietic stem cell transplantation (chemo/alloHSCT) than autologous transplant (autoHSCT) patients (interaction P = 0·04). Given the challenges of analysing bleeding data across both trials in an updated Cochrane review, a recurrent event analysis was also considered, which allows the investigation of all available bleeding data, rather than just focusing on measures such as rates of bleeding in patients or time to first bleeding event. Multivariate analyses of TOPPS trial data investigated patient factors and clinical characteristics associated with bleeding. Of 16 982 daily bleeding records analysed for 592 patients, grade 2–4 bleeding was reported in 700 (4%). Skin bruising was the most common type of bleed, reported on 32% of days when bleeding was reported to have occurred. Baseline characteristics associated with the number of days of bleeding were investigated: patients in the no‐prophylaxis arm of the study, patients who received a red cell transfusion in the previous 3 days, female patients and chemo/alloHSCT patients had the highest hazard of a grade 2–4 bleed. Additional analyses also found increased hazard of bleeding associated with the number of days with a platelet count >10 × 109/l for chemo/alloHSCT patients and high patient temperatures. In summary, there is evidence that the effectiveness of prophylactic platelet transfusions differs between subgroups of patients with haematological malignancies, with chemo/alloHSCT patients receiving prophylactic platelet transfusions showing a greater reduction in bleeding outcomes compared to patients following a no‐prophylaxis policy; there is no evidence that a prophylactic policy for platelet transfusion is a superior policy for patients receiving autoHSCT. As many patients continue to bleed despite transfusion of prophylactic platelet transfusions, additional strategies are required to prevent or minimize bleeding in all patient groups. Risk factors such as duration of severe thrombocytopenia or fever/inflammation appear more relevant factors to predict bleeding risk.