Rationale: Management of anticoagulant therapy is a common problem in patients with thrombocytopenia secondary to cancer or antitumoral therapies. Anticoagulant therapy may be prescribed for various other conditions. These include venous thromboembolism (TEV), atrial fibrillation, prosthetic heart valves.
For the management of anticoagulant therapy in cancer patients with thrombocytopenia the latest clinical practice guidelines are based on expert opinions but few retrospective studies, mainly focused on the use of low-molecular-weight heparin (LMWH). Their recommendations are mostly similar: they suggest halving the dose of LMWH, or using prophylactic doses when the platelet count is lower than 50×109/L but higher than 25×109/L; anticoagulant therapy should be withdrawn if the platelet count drops below 25×109/L.
In the acute phase of TEV it is sometimes recommended to use therapeutic doses of LMWH after transfusion of platelet concentrates, or else to insert vena caval filters.
Generally patients with thrombocytopenia receive suboptimal treatment, on account of the high risk of bleeding, and the lack of data on the safety and efficacy of anticoagulants in these situations means clinical decisions are based largely on the physician’s subjective opinion. There is therefore still a need for more information on the best way to manage anticoagulant therapy and the outcomes in cancer patients, especially those with hematological malignancies, with severe thrombocytopenia.
These considerations have led to the design of the present prospective study in patients with hematological malignancies, and thrombocytopenia, concomitantly receiving anticoagulant therapies; the aim is to quantify the incidence of hemorrhagic and thrombotic complications and identify the best strategies for managing anticoagulant treatment.
Objectives: The main aim of the pilot phase of the study is to investigate, in patients with hematological malignancies who need anticoagulants for any indication, what are the main decision-making paths physicians use in clinical practice to manage anticoagulant therapy when thrombocytopenia becomes severe after chemotherapy. The study will also calculate the incidence of hemorrhage and thrombosis after each clinical decision.
Analysis of the outcomes will be optimised on the basis of the results of the pilot phase, with the main aim of establishing the relative risk of bleeding and/or thrombosis for each therapeutic decision (to carry on or stop the treatment) in case of thrombocytopenia; the optimal platelet count cut-off will be calculated, at which anticoagulants can be effective and safe.
Study design: MATTER is a multicenter observational prospective center, in two phases:
1) Observational records (pilot phase);
2) Observational prospective cohort study.
The pilot phase is descriptive, posing the following research question: “In clinical practice what is the cut-off for the platelet count below which a concomitant anticoagulant treatment is modified or withdrawn, in patients with hematological malignancies and an indication for anticoagulation?”
The second phase is designed as a cohort study, optimised on the basis of the results of the pilot phase, with the following question: “In patients with hematological malignancies and severe thrombocytopenia (<50×109/L), with an indication for anticoagulation, what is the relative risk of bleeding and/or thrombosis if anticoagulant therapy is continued rather than withdrawn ?“
Expected results: This study should indicate the size of the problem, to start with, and these findings will serve for planning prospective intervention studies. The data will also point to the most promising management strategies.