Management of hyperleukocytosis and impact of leukapheresis among patients with acute myeloid leukemia (AML) on short- and long-term clinical outcomes: a large, retrospective, multicenter, international study

Complete elimination of hyperleukocytosis risk in AML through early high-quality disease remission

Background

Acute myeloid leukemia (AML) with hyperleukocytosis (HL) is a severe medical emergency associated with high mortality rates and poor prognosis. Prompt and urgent treatment is crucial to address this medical emergency. This study aims to elucidate appropriate diagnostic thresholds for HL and investigate underlying mechanisms and potential targeted therapies.

Methods

X-tile software was employed to analyze white blood cell (WBC) count thresholds in AML patients using data from TCGA and TARGET AML databases. METASCAPE and Gene Set Enrichment Analysis (GSEA) were conducted to explore the molecular mechanisms underlying HL in AML. Potential molecular targeted drugs were identified using the CELLMINER platform.

Results

Analysis revealed that a WBC count threshold of 75×109/L, rather than the conventional 100×109/L, is more appropriate for diagnosing HL in adult AML patients. This revised threshold could aid clinicians in identifying a greater number of patients requiring immediate intervention. Significant correlations were observed between HL and specific mutations, including NPM1, FLT3, and DNMT3A. For pediatric AML patients, the HL threshold was determined to be 165×109/L. Achieving complete remission (CR) or deeper levels of remission significantly reduces the risks associated with HL. The reduction in risk can lead to survival outcomes for HL patients that are comparable to those of non-hyperleukocytosis patients. Differential gene expression analysis indicated that downregulation of cell adhesion molecules is implicated in HL pathogenesis. Potential targeted therapies for AML with HL include Bcl2 inhibitors and histone deacetylase inhibitors. Clinical observations demonstrated that the addition of Bcl2 inhibitors, such as Venetoclax, to standard therapy results in a rapid reduction in WBC counts, thereby reducing tumor burden and providing prompt symptom relief. Combining these targeted drugs with conventional therapies appears promising in mitigating risks associated with HL.

Conclusions

Lower diagnostic thresholds for HL in AML, identifies critical genetic correlations, and highlights effective molecular targeted therapies. Proactive early treatment is crucial for achieving deep remission and reducing HL risk. Future therapeutic strategies should consider integrating molecular targeted drugs with conventional therapies to improve outcomes for patients facing this high-risk hematological emergency.

Management of hematological patients requiring emergency chemotherapy in the intensive care unit

Hematological malignancies may require rapid-onset treatment because of their short doubling time, notably observed in acute leukemias and specific high-grade lymphomas. Furthermore, in targeted onco-hematological scenarios, chemotherapy is deemed necessary as an emergency measure when facing short-term, life-threatening complications associated with highly chemosensitive hematological malignancies. The risks inherent in the disease itself, or in the initiation of treatment, may then require admission to the intensive care unit (ICU) to optimize monitoring and initial management protocols. Hyperleukocytosis and leukostasis in acute leukemias, tumor lysis syndrome, and disseminated intravascular coagulation are the most frequent onco-hematological complications requiring the implementation of emergency chemotherapy in the ICU. Chemotherapy must also be started urgently in secondary hemophagocytic lymphohistiocytosis. Tumor-induced microangiopathic hemolytic anemia and plasma hyperviscosity due to malignant monoclonal gammopathy represent infrequent yet substantial indications for emergency chemotherapy. In all cases, the administration of emergency chemotherapy in the ICU requires close collaboration between intensivists and hematology specialists. In this review, we provide valuable insights that aid in the identification and treatment of patients requiring emergency chemotherapy in the ICU, offering diagnostic tools and guidance for their overall initial management.

The ISTH DIC-score predicts early mortality in patients with non-promyelocitic acute myeloid leukemia

Coagulation disorders frequently complicate the clinical course of acute myeloid leukemia (AML) patients. This study examined the frequency and prognostic significance, with regards of early mortality, of the presence of overt disseminated intravascular coagulation (DIC) at AML diagnosis and its correlation with clinical and biological characteristics. A retrospective analysis of 351 newly diagnosed non-promyelocytic AML patients was conducted, utilizing the 2018 ISTH DIC-Score criteria to evaluate the presence of overt DIC at AML onset. The study cohort had a median age of 65 years with a predominance of male gender (59 %). Overt DIC was present in 21 % of cases and was associated with advanced age, comorbidities, poor performance status, hyperleukocytosis, LDH levels, NPM1 mutations, expression of CD33 and CD4, and lack of expression of CD34. With a median follow-up of 72 months (3-147 months), the 6-year overall survival (OS) was 17.4 %, with patients having overt DIC showing significantly poorer outcomes (7.2 % compared to 20.3 % of those without DIC, p < 0.001). Patients with overt DIC showed markedly high early mortality rates at 30 (42.5 % vs 8 %), 60 (49.3 % vs 16.9 %), and 120 days (64.4 % vs 25.6 %) from disease onset. In multivariate analysis overt DIC retained its independent prognostic value for early mortality. In conclusion, the prevalence and clinical relevance of DIC in non-promyelocytic AML is not negligible, underlining its potential as an unfavorable prognostic marker. In newly diagnosed patients with AML, early recognition and measure to counteract coagulation disturbances might help mitigate the elevated mortality risk associated with DIC.

Prognostic significance of the frequencies of bone marrow lymphocyte subsets in adult acute myeloid leukemia at diagnosis

INTRODUCTION

Immune microenvironment plays an important role in the occurrence and development of acute myeloid leukemia (AML). Studies assessing the prognostic significance of bone marrow (BM) lymphocyte subsets' frequencies at diagnosis in patients with AML were limited.

METHODS

Fresh BM samples collected from 97 adult AML patients at diagnosis were tested for lymphocyte, T, CD4+ T, CD8+ T, γδT, NK, and B cell frequencies using multi-parameter flow cytometry.

RESULTS

Low frequencies of lymphocytes, T, CD4+ T, and CD8+ T cells were associated with significantly lower rates of one-course complete remission (CR) (all p < 0.05). Moreover, the frequency of CD4+ T cells independently predicted one-course CR achievement (p = 0.021). Low frequencies of T and CD8+ T cells were significantly associated with lower relapse-free survival (RFS) rates (p = 0.032; 0.034), respectively, and a low frequency of CD8+ T cells was associated with a significantly lower overall survival (OS) rate (p = 0.028). Combination of frequency of CD8+ T cells and ELN risk stratification showed that patients with ELN-intermediate/adverse risk + high CD8+ T cell frequency had a similar RFS rate to those with ELN-favorable risk + high CD8+ T cell frequency and those with ELN-favorable risk + low CD8+ T cell frequency (p = 0.88; 0.76), respectively. The RFS rate of patients with ELN intermediate/adverse risk + low CD8+ T cell frequency was significantly lower than that of all aforementioned patients (p = 0.021; 0.0007; 0.028), respectively.

CONCLUSION

The frequencies of BM lymphocyte subsets at diagnosis predicted clinical outcomes and could help improve risk stratification in AML.

Red cell exchange for rapid leukoreduction in adults with hyperleukocytosis and leukostasis

ABSTRACT

We show that red cell exchange (RCE) treats hyperleukocytosis in acute leukemia. RCE provided similar leukoreduction to standard therapeutic leukoreduction and could be superior in patients with severe anemia or monocytic leukemias or when requiring rapid treatment.

Cardiovascular collapse and McConnell's sign as early manifestations of leucostasis

A man in his late 70s with chronic myelomonocytic leukaemia presented for evaluation of acute leukaemic transformation and initiation of cytoreductive therapy after being found to have asymptomatic hyperleucocytosis. Within 24 hours, the patient developed vasopressor-refractory shock, severe lactic acidosis and multiorgan failure. Serial echocardiographic assessments revealed interval enlargement of the right ventricle with development of the McConnell's sign, and abdominal CT showed diffuse bowel wall thickening, likely due to ischaemia. CT angiography excluded pulmonary embolism or occlusion of intra-abdominal arteries. Despite aggressive care, the patient died from cardiovascular collapse within 8 hours of the onset of hypotension. An autopsy revealed extensive infiltration of early myeloid cells in pulmonary, myocardial, hepatic and intestinal microvasculature. This case illustrates different mechanisms by which leucostasis causes acute cardiovascular collapse and stresses the emergent nature of this diagnosis.

[Cancer patients in the emergency department]

A growing number of patients are living with cancer or have a history of cancer leading to increasing adverse effects of treatment or disease necessitating emergency department (ED) consultation. Long-term cancer survivors are at higher risk of comorbidities causing a substantial increase in health care resource utilization. The most frequent reasons for cancer-related ED visits are dyspnea, fever, pain, gastrointestinal or neurological symptoms leading to high hospital and intensive care unit admission rates. Acute respiratory failure in cancer patients necessitates timely diagnostic testing, whereby computed tomography is superior to chest X‑ray. Delay in intensive care unit (ICU) admission or mechanical ventilation increases mortality. Febrile neutropenia is an emergency with urgent need for antibiotic treatment. Treatment of neutropenic and nonneutropenic patients with sepsis does not differ. Cardiovascular disease is now the second leading cause of long-term morbidity and mortality among cancer survivors. Immunotherapy can lead to substantial and in some patients life-threatening complications that may not easily be recognized in the ED. Cancer-specific emergencies such as leukostasis, tumorlysis or hypercalcemia rarely present to ED and require interdisciplinary care. The constantly growing cancer population is likely to increase ED utilization. Knowledge about cancer treatment and disease-associated complications is crucial for emergency physicians. Palliative care education should secure appropriate end-of-life care avoiding futile interventions.

Symptomatic Patients with Hyperleukocytic FLT3-ITD Mutated Acute Myeloid Leukemia Might Benefit from Leukapheresis

PURPOSE

We aimed to identify subsets of patients who benefit from emergency LA and to establish a therapeutic algorithm for AML patients with hyperleukocytosis.

METHODS

In this single-center retrospective cohort study, a total of 20 consecutive patients underwent LA because of their clinical symptoms. Overall survival (OS) analysis was conducted using the Kaplan-Meier plot method. Univariate and multivariate analyses (using multiple logistic regression) were performed. At the time of diagnosis, all patients received a standard diagnostic workup for AML including FLT3-ITD mutational analysis.

RESULTS

FLT3-ITD mut AML patients receiving LA had a median OS of 437 days (range 5-2379 days) with a corresponding 14-day survival of 92.3%, while FLT3 wt AML patients displayed a significantly lower median OS of only 5 days (range 1-203 days) with a corresponding 14-day survival of 14.3% (p = 0.0001).

CONCLUSIONS

Among patients with clinical symptoms of leukostasis, the subset of FLT3-ITD mut AML patients showed a better outcome with lower early mortality after emergency LA. Based on these observations, we established a therapeutic algorithm for AML patients with hyperleukocytosis.

Effectiveness of leukapheresis on early survival in acute myeloid leukemia: An observational propensity score matching cohort study

BACKGROUND

The association between leukapheresis (LK) as a treatment option for hyperleukocytosis (HL) in patients with acute myeloid leukemia (AML) remains controversial.

METHODS

Data were extracted from the electronic medical record for 2801 patients with AML between April 2009 and December 2019. LK was performed when the leukocyte count was ≥100 × 109 /L at the time initial bone marrow examination.

RESULTS

A comparison between the patients with HL in the non-LK (n = 1579) and LK (n = 208) groups revealed survival probabilities (%) of 93.2% and 90.4% (P = .130) for day 30 (D30), 85.4% and 84.2% (P = .196) for D60, and 83.6% and 80.8% (P = .258) for D90, respectively. After propensity score matching, a comparison between the patients with HL in the non-LK (n = 192) and LK (n = 192) groups revealed survival probabilities (%) of 83.9% and 91.2% (P = .030) for D30, 75.0% and 84.9% (P = .015) for day 60 (D60), and 62.4% and 81.3% (P = .034) for day 90 (D90), respectively. After D150, the observed effect of LK appeared to be mitigated without a survival benefit.

DISCUSSION

LK was associated with improved early survival outcomes at D30, D60, and D90 among patients with AML exhibiting HL. Thus, it may be considered a treatment option for reducing cell mass in such patients.

Clinico-Radio-Pathologic Correlation of Leukostasis in Acute Myeloid Leukemia with FLT3 Mutation

The systemic complications of acute hematologic emergencies account for the high mortality rates seen during inpatient management. Perhaps the most challenging diagnostic entity among all hematologic emergencies is leukostasis. In acute myeloid leukemia (AML), myeloid blasts are often highly adherent to the endothelial vasculature, and high peripheral blood blast count in excess of 100,000 cells per microliter can predispose patients to pulmonary and neurologic complications, leading to rapid clinical deterioration even before a formal diagnosis of leukostasis is made. The mobilization of appropriate healthcare personnel in the inpatient setting at inopportune times sometimes poses a major barrier to the successful treatment of patients with leukostasis, and patients can pass away quickly. In this report, we describe clinico-radio-pathologic correlations of leukostasis using pre- and post-mortem analysis in a patient with AML with a FLT3-TKD mutation, and we describe the current literature on best management approaches based on recent evidence, including consideration of first-line FLT3 (CD135) inhibitors such as quizartinib.

Genetic mutations and leukapheresis in acute myeloid leukemia: is there a link?

Acute myeloid leukemia is the most common acute leukemia in adults and up to 20% of patients present with hyperleukocytosis at the onset of the disease. The therapeutic approach involves medical support, cytoreductive treatment, and/or leukapheresis. Despite WBC count greater than 100.000/μL, not all patients develop symptoms. To clarify the role of leukapheresis in the setting of hyperleukocytotic AML, we aimed to find associations between AML morphologic subtypes and molecular alterations on presence or absence of leukostasis symptoms (and hence therapeutic vs prophylactic leukapheresis) and clinical outcomes in the cohort of 41 patients at our single center who underwent leukapheresis for hyperleukocytotic AML. There was a trend for increased WBC count, 30-day mortality, M4-M5 AML subtypes, and number of leukapheresis procedures performed in symptomatic hyperleukocytotic pts. No molecular marker was significantly associated with presence or absence of leukostasis symptoms due to small sample size, though there was a trend for increased NPM1-mutated and NPM1 + FLT3-mutated AML in asymptomatic patients and a greater proportion of symptomatic patients who were negative for all assessed molecular alterations. In conclusion, leukapheresis combined with cytoreductive treatment represents a synergic and efficient approach in the management of hyperleukocytosis especially in symptomatic patients considering the higher mortality independently from the presence of specific clonal markers whose distribution among the two groups may result more considerable with a higher number of patients.

Hyperleukocytosis in patients with acute myeloid leukemia admitted to the intensive care unit: a single-center retrospective analysis

A relevant proportion of patients with acute myeloid leukemia (AML) presenting with hyperleukocytosis are admitted to the intensive care unit (ICU). However, data on characteristics and outcomes of these patients are limited. We therefore conducted a single-center retrospective analysis including 69 consecutive AML patients with a white blood cell (WBC) count > 100.000/µl who had been treated on the ICU between 2011 and 2020. The median age was 63 years (range: 14-87 years). Males accounted for the majority of cases (n = 43; 62.3%). Mechanical ventilation (MV), renal replacement therapy and the use of vasopressors were necessary in 34.8%, 8.7% and 40.6% of patients, respectively. Cardiopulmonary resuscitation was performed in 15.9% of patients. The ICU, hospital, 90-day and 1-year survival rates were 53.6%, 43.5%, 42% and 30.4%, respectively. Age (p = 0.002), SOFA score (p < 0.001) and MV (p < 0.001) were independently associated with a reduced survival probability. A score comprising the factors age > 70 years, lactate dehydrogenase level > 1500 U/l, WBC count > 150.000/µl, elevated lactate level and SOFA score > 7 allowed the discrimination of 3 distinct risk groups (low-risk: 0-1 points, intermediate-risk: 2 points, high-risk: 3-5 points) with regard to survival (p < 0.0001). Taken together, the present analysis indicates that more than two-thirds of AML patients with hyperleukocytosis treated on the ICU die within 1 year. However, outcomes vary considerably depending on the presence of risk factors.

Acute vision loss due to CML leukemic retinopathy reversed with leukapheresis

Leukemic retinopathy is a severe complication of severe leukocytosis that results from untreated chronic myelogenous leukemia (CML). Immediate cytoreduction via leukapheresis may reverse ocular manifestations and prevent permanent vision damage. We present a case of a patient with acute unilateral vision loss found to have leukemic retinopathy in the setting of untreated CML with improvement of visual symptoms after leukapheresis and initiation of hydroxyurea.

Take a spin: Apheresis in the care of adult leukaemia patients

Apheresis is an automated process to separate the whole blood of a patient or a donor, collect or remove specific blood components, and return the remaining back to the individual. Apheresis is an integral part of blood and marrow transplantation and has been increasingly utilized in novel cellular therapies for a variety of blood disorders. This review uses clinical cases to highlight the multiple roles of apheresis in the care of adult leukaemia patients, including therapeutic leukapheresis in hyperleukocytosis, mobilized peripheral blood hematopoietic progenitor cell collection in donors, mononucleated cell collection in preparation of donor lymphocyte infusion or chimeric antigen receptor T cells manufacture, and extracorporeal photopheresis in the treatment of graft versus host diseases.

Benefits of dexamethasone on early outcomes in patients with acute myeloid leukemia with hyperleukocytosis: a propensity score matched analysis

Hyperleukocytosis is associated with a significant early mortality rate in patients with acute myeloid leukemia (AML). To date, no controlled trial has ever evaluated a strategy to reduce this risk, and the initial management of these patients remains heterogeneous worldwide. The aim of the present study was to evaluate the influence of a short course of intravenous dexamethasone on the early outcomes of patients with hyperleukocytic AML with white blood cell (WBC) count above 50 × 10⁹/L. Clinical and biological data of all consecutive patients (1997-2017) eligible for intensive chemotherapy from a single center were retrospectively collected. A total of 251 patients with a median age of 51 years and a median WBC count of 120 × 10⁹/L were included, 95 of whom received dexamethasone. Patients treated with dexamethasone had higher WBC count and a more severe disease compared with those who did not, and they presented more often with leukostasis and hypoxemia, resulting in a more frequent need for life-sustaining therapies (p < 0.001). To account for these imbalances, patients were compared after adjusting for a propensity score, which included all variables with a prognostic influence in the overall cohort. In the matched cohort, dexamethasone was associated with lower early death (OR = 0.34, p = 0.0026) and induction failure rate (OR = 0.44, p = 0.02) and better overall survival (HR = 0.60, p = 0.011), with no impact on relapse risk (cHR = 0.73, p = 0.39). The overall survival benefit was confirmed among all tested subgroups. This study suggests that dexamethasone administration is safe and associated with a lower risk of induction mortality in patients with hyperleukocytic AML and deserves prospective evaluation.

A potential area of use for immune checkpoint inhibitors: Targeting bone marrow microenvironment in acute myeloid leukemia

Acute myeloid leukemia (AML) arises from the cells of myeloid lineage and is the most frequent leukemia type in adulthood accounting for about 80% of all cases. The most common treatment strategy for the treatment of AML includes chemotherapy, in rare cases radiotherapy and stem cell and bone marrow transplantation are considered. Immune checkpoint proteins involve in the negative regulation of immune cells, leading to an escape from immune surveillance, in turn, causing failure of tumor cell elimination. Immune checkpoint inhibitors (ICIs) target the negative regulation of the immune cells and support the immune system in terms of anti-tumor immunity. Bone marrow microenvironment (BMM) bears various blood cell lineages and the interactions between these lineages and the noncellular components of BMM are considered important for AML development and progression. Administration of ICIs for the AML treatment may be a promising option by regulating BMM. In this review, we summarize the current treatment options in AML treatment and discuss the possible application of ICIs in AML treatment from the perspective of the regulation of BMM.

Development of clinical pathways to improve multidisciplinary care of high-risk pediatric oncology patients

Clinical pathways are evidence-based tools that have been integrated into many aspects of pediatric hospital medicine and have proven effective at reducing in-hospital complications from a variety of diseases. Adaptation of similar tools for specific, high-risk patient populations in pediatric oncology has been slower, in part due to patient complexities and variations in management strategies. There are few published studies of clinical pathways for pediatric oncology patients. Pediatric patients with a new diagnosis of leukemia or lymphoma often present with one or more “oncologic emergencies” that require urgent intervention and deliberate multidisciplinary care to prevent significant consequences. Here, we present two clinical pathways that have recently been developed using a multidisciplinary approach at a single institution, intended for the care of patients who present with hyperleukocytosis or an anterior mediastinal mass. These clinical care pathways have provided a critical framework for the immediate care of these patients who are often admitted to the pediatric intensive care unit for initial management. The goal of the pathways is to facilitate multidisciplinary collaborations, expedite diagnosis, and streamline timely treatment initiation. Standardizing the care of high-risk pediatric oncology patients will ultimately decrease morbidity and mortality associated with these diseases to increase the potential for excellent outcomes.

Diagnosis and management of AML in adults: 2022 recommendations from an international expert panel on behalf of the ELN

The 2010 and 2017 editions of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults are widely recognized among physicians and investigators. There have been major advances in our understanding of AML, including new knowledge about the molecular pathogenesis of AML, leading to an update of the disease classification, technological progress in genomic diagnostics and assessment of measurable residual disease, and the successful development of new therapeutic agents, such as FLT3, IDH1, IDH2, and BCL2 inhibitors. These advances have prompted this update that includes a revised ELN genetic risk classification, revised response criteria, and treatment recommendations.

Molecular dissection of a hyper-aggressive CBFB-MYH11/FLT3-ITD-positive acute myeloid leukemia

Acute Myeloid Leukaemia (AML) is a haematological malignancy showing a hypervariable landscape of clinical outcomes and phenotypic differences, explainable by heterogeneity at the cellular and molecular level. Among the most common genomic alterations, CBFB-MYH11 rearrangement and FLT3-ITD gene mutations, have opposite clinical significance and are unfrequently associated. We present here a Molecular Case Report in which these two events co-exist an ultra-aggressive phenotype resulting in death in 4 days from hospital admittance. Somatic and germline Whole Exome Sequencing analysis was performed to uncover other putative driver mutations, de-novo genomic structural events or germline clusters increasing cancer insurgence. Only three mutations in LTK, BCAS2 and LGAS9 were found, unlikely causative of the exhibited phenotype, prompting to additional investigation of the rare CBFB-MYH11/ FLT3-ITD scenario.

Urgent cytoreduction for newly diagnosed acute myeloid leukemia patients allows acquisition of pretreatment genomic data and enrollment on investigational clinical trials

Newly diagnosed acute myeloid leukemia is often deemed a medical emergency, requiring urgent treatment. This is in contradiction with the need for accurate cytogenetic and molecular data, which is not immediately available, to select optimal therapy. We hypothesized that cytoreduction with hydroxyurea or cytarabine would enable urgent disease control and provide a bridge to clinical trial enrollment. We analyzed three prospective frontline clinical trials that allowed the use of cytoreduction before treatment initiation. Among 274 patients with a median age of 62 (range, 18-89), there was no significant difference in short- and long-term outcome and safety among patients who did (CytoRed) or did not receive (NoCytoRed) cytoreduction. The overall response rate in CytoRed group was 91%, compared with 86% in NoCytoRed group (p = .264). The 30- and 60-day mortality rates were 2% and 7% in CytoRed group, compared with 2% (p = .978) and 6% (p = .652) in NoCytoRed group, respectively. There was no significant difference in overall survival (OS) between in CytoRed group compared with NoCytoRed group (Hazard ratio 0.97, 95% CI 0.70-1.37, p = .879). Results were unchanged after stratification by age (< or ≥65 years) or after multivariate analyses for OS. Our data suggests that urgent cytoreduction using hydroxyurea or cytarabine is a feasible and safe approach to facilitate acquisition of complete diagnostic information prior to treatment initiation on a clinical trial.

Leukapheresis in Pediatric Acute Leukemia with Hyperleukocytosis: A Single-Center Experience

Hyperleukocytosis in pediatric acute leukemia is associated with increased morbidity and mortality and at present there is no consensus on the use of leukapheresis (LPH) for its management. Our aim was to review characteristics and outcomes of newly diagnosed leukemia patients with hyperleukocytosis (HL) comparing those who received LPH and those who did not. An IRB approved retrospective case control study reviewed data from a single institution over a 10 year period. At our institution, LPH was used in 8 of 62 (13%) patients with hyperleukocytosis with minimal complications. Mean leukocyte count in patients who received LPH versus those who did not was 498 k cells/mm³ and 237 k cells/mm³, respectively. Patients who had symptoms of neurologic (63 vs. 17%) or pulmonary leukostasis (75 vs. 17%) were more likely to have undergone leukapheresis. The time from presentation to the initiation of chemotherapy was not different between those who received LPH and those who did not (mean of 35 h vs. 34 h). There was one death in the LPH group, that was the result of neurologic sequelae of hyperleukocytosis and not LPH itself. The use of LPH in patients with hyperleukocytosis is safe, well tolerated and does not alter time to chemotherapy at our institution.

The Bone Marrow Microenvironment Mechanisms in Acute Myeloid Leukemia

Bone marrow (BM) is a highly complex tissue that provides important regulatory signals to orchestrate hematopoiesis. Resident and transient cells occupy and interact with some well characterized niches to produce molecular and cellular mechanisms that interfere with differentiation, migration, survival, and proliferation in this microenvironment. The acute myeloid leukemia (AML), the most common and severe hematological neoplasm in adults, arises and develop in the BM. The osteoblastic, vascular, and reticular niches provide surface co-receptors, soluble factors, cytokines, and chemokines that mediate important functions on hematopoietic cells and leukemic blasts. There are some evidences of how AML modify the architecture and function of these three BM niches, but it has been still unclear how essential those modifications are to maintain AML development. Basic studies and clinical trials have been suggesting that disturbing specific cells and molecules into the BM niches might be able to impair leukemia competencies. Either through niche-specific molecule inhibition alone or in combination with more traditional drugs, the bone marrow microenvironment is currently considered the potential target for new strategies to treat AML patients. This review describes the cellular and molecular constitution of the BM niches under healthy and AML conditions, presenting this anatomical compartment by a new perspective: as a prospective target for current and next generation therapies.

Acute leukemia presenting as acute lower limb ischemia

Objectives: Acute lower limb ischemia (ALLI) is a common vascular emergency. However, ALLI presenting as the initial symptom of acute leukemia (AL) is scarce. Here we present a case of ALLI in the setting of acute myeloid leukemia (AML) while systematically reviewing the current literature to withdraw conclusions about the management, prognosis, and treatment for this atypical presentation of AL. Methods: We conducted a systematic electronic research according to Preferred Reporting Items for Systematic Review and Meta-Analysis protocol (PRISMA) for articles published from January 1981 up to January 2021 concerning ALLI in the setting of acute leukemia (AL). Patients' baseline characteristics were recorded and nine outcomes of interest were studied. Results: Twenty-six individuals, 16 males with a mean age of 46.3 years (±20) were included in this review. The diagnosis included 13 AML patients (50%), 11 acute promyelotic leukemia (APL) (42.3%) and two acute lymphoblastic leukemias (ALL) (7.7%). Treatment varied among nine different regimens. Four patients were treated with chemotherapy alone (15.4%), four with thrombectomy alone (15.4%), and 11 with a combination of chemotherapy and thrombectomy (42.3%). Eight major amputations were recorded (30. 8%). Thirty-day mortality was 35.7%. Forty-eight peripheral thrombotic events were recorded with 12 patients suffering recurrent thrombotic events. Conclusion: ALLI as the presenting symptom of AL is a rare condition that carries significant mortality and amputation rates. Timely diagnosis is crucial concerning short-term survival and limb salvage. APL, despite being the rarest form of AL, represented a significant proportion of the patient population in this review. The role of leukostasis in the disease's progression and the efficacy of leukapheresis as a treatment regimen should be further investigated through case-control studies.

Management Approach to Acute Myeloid Leukemia Leveraging the Available Resources in View of the Latest Evidence: Consensus of the Saudi Society of Blood and Marrow Transplantation

Acute myeloid leukemia (AML) is the most prevalent acute leukemia in adults and is responsible for the majority of cancer-related mortality. In Saudi Arabia, leukemia is ranked the fifth most prevalent type of malignancy in adults. Our aim is to review existing epidemiologic data in Saudi Arabia and develop consensus guidelines for management of AML.

Leukapheresis and Hyperleukocytosis, Past and Future

Hyperleukocytosis is a hematologic crisis caused by excessive proliferation of leukemic cells and has a relatively high early mortality due to a series of severe complications. Therefore, prompt and effective intervention is required. Leukapheresis performed using apheresis equipment to separate leukocytes from peripheral blood, at the same time returns autologous plasma, platelets and erythrocytes to the patient, is applied clinically for the treatment of hyperleukocytosis. Leukapheresis not only removes excessive leukocytes rapidly and corrects metabolic abnormalities but also alleviates the symptoms of leukostasis. In addition, the procedure of leukapheresis is generally well tolerated. Leukapheresis has become one of the most imperative adjuvant therapies to treat hyperleukocytosis, especially in the patient who was not inappropriate to cytoreduce with Ara-C or hydroxyurea. In this review, we present the background of leukapheresis development and highlight its clinical application in hyperleukocytic leukemia patients.

Leukapheresis Does Not Improve Early Survival Outcome of Acute Myeloid Leukemia with Leukostasis Patients - A Dual-Center Retrospective Cohort Study

Introduction

Leukostasis is a medical emergency with high mortality which often occurs in acute myeloid leukemia patients with hyperleukocytosis. One of the therapies that can be used for leukostasis in acute myeloid leukemia is leukapheresis. However, whether leukapheresis can provide better survival benefit when compared with patients not receiving leukapheresis is still unclear. Hence, we aimed to evaluate the effect of chemotherapy plus leukapheresis combination versus chemotherapy only on 28-day survival of acute myeloid leukemia patients with leukostasis.

Methods

This study was a dual-center retrospective cohort using secondary data from medical records collected from November 2018 to March 2019. Inclusion criteria were adult patients aged 18 years old or above, diagnosed with acute leukemia with hyperleukocytosis status defined by WBC count greater than 100,000/uL, and with symptoms of leukostasis. One-month survival analysis was conducted using Kaplan–Meier curve method. Univariate and multivariate analyses were then conducted using Cox proportional hazards model to obtain value of hazard ratio (HR) with a 95% confidence interval (CI).

Results

A total of 38 patients were obtained for analysis. The median overall survival was 25 days (95% CI: 17.001–32.999 days) in the chemotherapy only group and 20 days (95% CI: 1.497–38.503) in the chemotherapy with leukapheresis group. The use of leukapheresis did not affect 28-day survival (HR: 1.140; 95% CI: 0.396–3.283; p value: 0.809) and 7-day survival (HR: 1.073; 95% CI: 0.277–4.152; p value: 0.919). In the multivariate analysis, age ≥60 years, blast percentage ≥90%, creatinine ≥1.4 mg/dL, and presence of disseminated intravascular coagulation were associated with worse 28-day survival.

Conclusion

AML patients with leukostasis who received both chemotherapy and leukapheresis did not have better 28-day survival and 7-day survival when compared with patients receiving chemotherapy only. Old age, high blast percentage, high creatinine, and presence of disseminated intravascular coagulation were prognostic factors for worse 28-day survival.

Effect of prophylactic leukapheresis on early mortality and overall survival in acute leukemia patients with hyperleukocytosis

Hyperleukocytosis has been associated with early mortality owing to the presence of complications including leukostasis, tumor lysis syndrome (TLS), and disseminated intravascular coagulation (DIC). Leukapheresis is a fast and effective cytoreductive procedure that removes leukocytes from the peripheral circulation. This single-center, retrospective, and observational study included 32 patients diagnosed with acute leukemia who underwent leukapheresis due to hyperleukocytosis between 2014 and 2020. This study primarily aimed to investigate the effect of prophylactic leukapheresis on early mortality and overall survival (OS). In the symptomatic group, seven and two patients died in the first and second weeks, respectively. In the prophylactic leukapheresis group, two and one patients died in the first and second weeks (p = 0.792), respectively. OS was significantly longer in the prophylactic leukapheresis group (p = 0.004). The leukapheresis procedure appears to be effective on early mortality and OS. Initiation of prophylactic leukapheresis before the appearance of leukostasis symptoms is effective on OS and possibly early mortality.

The factors influencing clinical outcomes after leukapheresis in acute leukaemia

Leukapheresis is used for the mechanical removal of leukaemic cells in hyperleukocytosis. However, the effectiveness of leukapheresis remains unclear due to selection and confounding factors in the cohorts. We compared the effectiveness of leukapheresis among the subgroups according to either the 2016 World Health Organization classification or the number of cytogenetic abnormalities with a retrospective, single-centre study from January 2009 to December 2018. Acute myeloid leukaemia (AML, n = 212) and acute lymphoblastic leukaemia (ALL, n = 97) were included. The 30-day survival rates (95% confidence interval, 95% CI) for AML and ALL were 86.3% (81.6–90.9%) and 94.8% (90.3–99.2%), respectively. For AML, ‘primary AML with myelodysplasia-related changes’ and ‘AML with biallelic mutation of CEBPA’ showed better 30-day survival outcomes (P = 0.026) than the other subgroups. A higher platelet count after leukapheresis was associated with better 30-day survival in AML patients (P = 0.029). A decrease in blast percentage count after leukapheresis was associated with better 30-day survival in ALL patients (P = 0.034). Our study suggested that prophylactic platelet transfusion to raise the platelet count to 50 × 10⁹/L or greater might improve clinical outcome in AML patients undergoing leukapheresis.

Pulmonary Manifestations of Hematologic and Oncologic Diseases in Children

Pulmonary complications are common in children with hematologic or oncologic diseases, and many experience long-term effects even after the primary disease has been cured. This article reviews pulmonary complications in children with cancer, after hematopoietic stem cell transplant, and caused by sickle cell disease and discusses their management.

NCCN Guidelines Insights: Acute Myeloid Leukemia, Version 2.2021

The NCCN Guidelines for Acute Myeloid Leukemia (AML) provide recommendations for the diagnosis and treatment of adults with AML based on clinical trials that have led to significant improvements in treatment, or have yielded new information regarding factors with prognostic importance, and are intended to aid physicians with clinical decision-making. These NCCN Guidelines Insights focus on recent select updates to the NCCN Guidelines, including familial genetic alterations in AML, postinduction or postremission treatment strategies in low-risk acute promyelocytic leukemia or favorable-risk AML, principles surrounding the use of venetoclax-based therapies, and considerations for patients who prefer not to receive blood transfusions during treatment.

High dose cyclophosphamide for cytoreduction in patients with acute myeloid leukemia with hyperleukocytosis or leukostasis

Hyperleukocytosis may lead to multiple medical emergencies. Hydroxyurea, intensive chemotherapy, and leukapheresis are used for cytoreduction. However, there is little data regarding the best approach. Here, we report on the efficacy and safety of high dose cyclophosphamide (HDCy; 60 mg/kg). 27 patients with acute myeloid leukemia or blast phase chronic myeloid leukemia who presented with white blood cell count (WBC) of ≥50x10⁹/L or symptoms of leukostasis were treated with HDCy. Primary endpoint was early mortality (death within seven days of admission). Median WBC was 107 × 10⁹/L at time of HDCy; 74% had leukostasis symptoms at presentation. Eight (29.6%) patients died within seven days of admission. Sustained WBC reduction was achieved in 18/24 (75%) evaluable patients with median nadir of 0.25 × 10⁹/L. Adverse effects attributed to HDCy included tumor lysis syndrome (n = 7; 25.9%), disseminated intravascular coagulopathy (n = 5; 18.5%), and hemorrhagic cystitis (n = 1; 3.7%). HDCy was effective for cytoreduction and adverse effects were acceptable.

Oncologic Emergencies: Traditional and Contemporary

The recognition and management of oncologic emergencies are becoming increasingly relevant in the intensive care unit, particularly in the era of novel biologic therapies. Early recognition and multidisciplinary collaboration are essential to improving patient outcomes. This article discusses aspects of diagnosis and management for important malignancy-associated emergencies.

Hyperleukocytosis and Leukostasis in Acute Myeloid Leukemia: Can a Better Understanding of the Underlying Molecular Pathophysiology Lead to Novel Treatments?

Up to 18% of patients with acute myeloid leukemia (AML) present with a white blood cell (WBC) count of greater than 100,000/µL, a condition that is frequently referred to as hyperleukocytosis. Hyperleukocytosis has been associated with an adverse prognosis and a higher incidence of life-threatening complications such as leukostasis, disseminated intravascular coagulation (DIC), and tumor lysis syndrome (TLS). The molecular processes underlying hyperleukocytosis have not been fully elucidated yet. However, the interactions between leukemic blasts and endothelial cells leading to leukostasis and DIC as well as the processes in the bone marrow microenvironment leading to the massive entry of leukemic blasts into the peripheral blood are becoming increasingly understood. Leukemic blasts interact with endothelial cells via cell adhesion molecules such as various members of the selectin family which are upregulated via inflammatory cytokines released by leukemic blasts. Besides their role in the development of leukostasis, cell adhesion molecules have also been implicated in leukemic stem cell survival and chemotherapy resistance and can be therapeutically targeted with specific inhibitors such as plerixafor or GMI-1271 (uproleselan). However, in the absence of approved targeted therapies supportive treatment with the uric acid lowering agents allopurinol and rasburicase as well as aggressive intravenous fluid hydration for the treatment and prophylaxis of TLS, transfusion of blood products for the management of DIC, and cytoreduction with intensive chemotherapy, leukapheresis, or hydroxyurea remain the mainstay of therapy for AML patients with hyperleukocytosis.

Leukocytapheresis for patients with acute myeloid leukemia presenting with hyperleukocytosis and leukostasis: a contemporary appraisal of outcomes and benefits

Introduction: Hyperleukocytosis, defined as a total white blood cell count (WBC) >50 or more commonly >100 × 10⁹ cells/L, is a presenting feature of acute myeloid leukemia (AML) in about 6-20% of cases and is associated with a higher risk of tumor lysis syndrome (TLS), disseminated intravascular coagulation (DIC), clinical leukostasis with end organ damage, and mortality.Areas covered: In this review, authors discuss the implications of hyperleukocytosis in AML and the current understanding of cytoreductive strategies with a focus on the use of leukocytapheresis.Expert commentary: Efforts to rapidly reduce peripheral myeloblasts have included the use of leukocytapheresis. Early studies demonstrated feasibility in reducing peripheral WBC and blast counts as well as clinically relevant patient outcomes which prompted its common use for many years. However, more recent data have directly challenged the previously touted reports of reduced TLS and DIC incidence as well as survival benefit, even in patients with clinical leukostasis. The use of leukocytapheresis remains highly controversial with wide practice variations among physicians, institutions, and countries given the lack of high-quality data, risks associated with leukocytapheresis itself, associated high costs, resource utilization, and lack of evidence-based clinical guidelines.