Thrombosis in Acute Myeloid Leukemia: Pathogenesis, Risk Factors and Therapeutic Challenges.

OPINION STATEMENT: Prophylaxis and treatment of thrombosis in leukemic patients still represent a major challenge with several clinical questions yet to be solved. Indeed, the paucity of evidence makes the management of venous thromboembolic events difficult and not uniform. Due to thrombocytopenia, patients with acute myeloid leukemia (AML) are underrepresented in trials investigating prophylaxis and treatment of thrombosis in cancer, and prospective data are lacking. Likewise, the therapeutic approach with anti-coagulants in leukemic patients is inferred from guidelines originally developed in the solid cancer setting and clear recommendations in the thrombocytopenic population are limited. Importantly, the discrimination of patients at high risk of bleeding from those with a predominant risk of thrombosis remains extremely difficult with no predictive score validated so far. Thus, the management of thrombosis often relies on clinician experience, and it is tailored to the individual patient, constantly balancing thrombotic and hemorrhagic risks. Who would benefit from primary prophylaxis and how a thrombotic event should be appropriately treated are some of the unanswered questions that the future guidelines and trials should address. Moreover, a greater effort should be made to identify robust predictive factors able to guide clinicians in the management of this potential serious complication for AML patients.

Frequency and risk factors for thrombosis in acute myeloid leukemia and high-risk myelodysplastic syndromes treated with intensive chemotherapy: a two centers observational study.

The frequency of thrombosis in AML has been evaluated only in a few studies and no validated predictive model is currently available. Recently, DIC score was shown to identify patients at higher thrombotic risk. We aimed to evaluate the frequency of thromboembolism in AML patients treated with intensive chemotherapy and to assess the ability of genetic and clinical factors to predict the thrombotic risk. We performed a retrospective observational study including 222 newly diagnosed adult AML (210) and high-risk MDS (12), treated with intensive chemotherapy between January 2013 and February 2020. With a median follow-up of 44 months, we observed 50 thrombotic events (90% were venous, VTE). The prevalence of thrombosis was 22.1% and the 6-months cumulative incidence of thrombosis was 10%. The median time to thrombosis was 84 days and 52% of the events occurred within 100 days from AML diagnosis. Khorana and DIC score failed to stratify patients according to their thrombotic risk. Only history of a thrombotic event (p = 0.043), particularly VTE (p = 0.0053), platelet count above 100 × 109/L at diagnosis (p = 0.036) and active smoking (p = 0.025) significantly and independently increased the risk of thrombosis, the latter particularly of arterial events. AML genetic profile did not affect thrombosis occurrence. Results were confirmed considering only thromboses occurring within day 100 from diagnosis. DIC score at diagnosis, but not thrombosis, was independently associated with reduced survival (p = 0.004). Previous VTE, platelet count above 100 × 109/L and active smoking were the only factors associate with increased thrombotic risk in AML patients treated intensively, but further studies are needed to validate these results.

Evolving Therapeutic Approaches for Older Patients with Acute Myeloid Leukemia in 2021.

Acute myeloid leukemia (AML) in older patients is characterized by unfavorable prognosis due to adverse disease features and a high rate of treatment-related complications. Classical therapeutic options range from intensive chemotherapy in fit patients, potentially followed by allogeneic hematopoietic cell transplantation (allo-HCT), to hypomethylating agents or palliative care alone for unfit/frail ones. In the era of precision medicine, the treatment paradigm of AML is rapidly changing. On the one hand, a plethora of new targeted drugs with good tolerability profiles are becoming available, offering the possibility to achieve a prolonged remission to many patients not otherwise eligible for more intensive therapies. On the other hand, better tools to assess patients' fitness and improvements in the selection and management of those undergoing allo-HCT will hopefully reduce treatment-related mortality and complications. Importantly, a detailed genetic characterization of AML has become of paramount importance to choose the best therapeutic option in both intensively treated and unfit patients. Finally, improving supportive care and quality of life is of major importance in this age group, especially for the minority of patients that are still candidates for palliative care because of very poor clinical conditions or unwillingness to receive active treatments. In the present review, we discuss the evolving approaches in the treatment of older AML patients, which is becoming increasingly challenging following the advent of new effective drugs for a very heterogeneous and complex population.