Thromboembolism in children with lymphoma

Sequelae and post-thrombotic syndrome after venous thromboembolism in acute lymphoblastic leukemia survivors treated on the NOPHO ALL2008 protocol

The treatment of acute lymphoblastic leukemia (ALL) is frequently complicated by toxicity, including venous thromboembolism (VTE) affecting roughly 8% of patients. VTE can lead to post-thrombotic syndrome (PTS), a group of signs and symptoms developed as a complication to deep venous thrombosis (DVT), imposing risk of permanent disability and reduced quality of life (QoL). PTS prevalence ranges from 0% to 70%, reflecting very heterogenous cohorts and assessment tools. We aimed to estimate sequelae, including PTS and QoL in children and adults (<45 years old) who had a DVT during ALL treatment. PTS and QoL scores were obtained through use of Villalta and Modified Villalta Scale, PedsQL, and Short Form-36 questionnaires. The cohort comprised 20 children (<18 years) and seven adults (median age: 12.9 years, range: 2-44 years) at the time of DVT diagnosis. In total, 25 ALL survivors underwent PTS examination. The examination took place when survivors were 7-48 years (median age: 20.3 years, median follow-up time 6.8 years). QoL was assessed correlating cases with three matching ALL survivors without VTE. Two adults (15.4%) showed mild or moderate PTS. Eight children (66.7%) were diagnosed with mild PTS, while three cases had collaterals as sole symptoms. Pain or symptoms affecting daily life were reported by 16%. No difference in QoL was found (p = .9). This study underscores the need for comprehensive population-based investigations with validation of PTS instruments in ALL survivors.

Incidence and Management of Thromboembolism in Patients with Acute Leukemia

Thromboembolic events (TE) in childhood are relatively rare but, serious complications of acute leukemia. The aim was to define the incidence and risk factors of thrombosis in children with leukemias. The electronic files of pediatric denovo/relapsed acute leukemia patients aged below 18 years, treated between 2011 and 2021 were retrospectively evaluated for thrombotic attacks. Thirty out of 469 patients developed 35 thrombotic events. The median age at the time of the TE was 11.8 (2-17.6) years, and the median time from diagnosis to TE was 9 (0-58) months. The frequency of TE was found at 7.4% (n = 35/469). When catheter related (n = 13) events, superficial venous events (n = 10), and arterial central nervous system thrombosis (n = 1) were excluded, the frequency of TE was decreased to 2.3% (n = 11/469). Children older than 10 years old (13.8%; n = 21/152) had significantly higher thromboembolic events than the others (4.4%; n = 14/317) (p = 0.03). The majority of attacks were symptomatic 66% (n = 23/35). The most common complaints were local pain, swelling, and redness 52% (n = 12/23). The majority of attacks in patients with relapsed (75%; 6/8) and newly diagnosed acute lymphoblastic leukemia (40%; 10/25%) developed during the induction phase. Thrombosis recurred in 13.3% (n = 4/30) of cases more than once. Thrombotic attacks were successfully treated with low molecular weight heparin 60% (n = 21/35), and recombinant tissue plasminogen activator 17% (n = 6/35). None of the children were lost due to thrombosis. Thrombosis is an important complication during acute leukemia treatment. Successful results are obtained with early diagnosis and treatment attempts by creating awareness.

Thrombotic complications in patients with cancer: Advances in pathogenesis, prevention, and treatment-A report from ICTHIC 2021

Venous thromboembolism (VTE) is a common complication in cancer patients, resulting in deep vein thrombosis (DVT) or pulmonary embolism (PE), and is responsible for high morbidity and mortality. This article discusses evidence and future perspectives on pathogenesis and prevention and treatment of thrombotic complications in patients with cancer. In April 2021, international basic researchers and clinicians met for the virtual edition of the 10th International Conference on Thrombosis & Hemostasis Issues in Cancer. Pathogenic mechanisms, markers and scores for risk assessment, diagnosis and therapy issues, current prophylaxis recommendations, and special settings, such as palliative care, pediatrics, and COVID-19 patients were discussed. Emerging areas of interest in cancer associated VTE are the role of immunotherapy, platelet activation markers, genetic alterations and real-world systems-based approaches to prevention and treatment.

Central venous catheter-associated complications in pediatric patients diagnosed with Hodgkin lymphoma: implications for catheter choice

Purpose

The purpose of this study was to determine the most optimal central venous catheter (CVC) for pediatric patients with Hodgkin lymphoma (HL) in terms of complications.

Methods

A retrospective study including patients diagnosed with HL from 2015 to 2021 at the Princess Máxima Center was performed. Patients were followed from CVC insertion until removal or 06–2021, whichever came first. The primary outcome was the CVC-related complication incidence rate (IR) per 1000 CVC-days. Furthermore, the incidence rate ratio (IRR) was calculated by comparing complication IRs between peripherally inserted central catheters (PICC) and totally implantable venous access ports (TIVAP). Additionally, risk factors for central venous thrombosis (CVT) were identified.

Results

A total of 98 patients were included. The most frequently observed complications were local irritation/infections (18%; IR 0.93), malfunctions (15%; IR 0.88), and CVC-related CVTs (10%; IR 0.52). Single lumen PICCs were associated with a higher risk of complications (49% vs. 26%; IRR 5.12, CI95% 2.76–9.50), severe complications (19% vs. 7%; IRR 11.96, CI95% 2.68–53.42), and early removal (18% vs. 7%; IRR 9.96, CI95% 2.18–45.47). A single lumen PICC was identified as a risk factor for CVC-related CVT when compared to TIVAPs (12% vs. 7%, IRR 6.98, CI95% 1.45–33.57).

Conclusion

The insertion of a TIVAP rather than a PICC should be recommended for pediatric patients with HL, especially in the presence of CVT-related risk factors. Future trials should evaluate the efficacy and safety of direct oral anticoagulants for the primary prevention of CVT in pediatric patients with a PICC and other CVT-related risk factors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00520-022-07256-3.

Primary thromboprophylaxis to prevent thrombotic events in pediatric oncology patients with a malignant mediastinal mass

Children with malignant mediastinal masses have increased thrombotic events (TE). Eligible subjects with malignant mediastinal masses between January 2000 and December 2017 were evaluated for TE, with 19 among 76 subjects receiving enoxaparin thromboprophylaxis. There were 13 TEs among 76 subjects for an incidence of 17.1%. Mediastinal compression directly led to TE in 9.2% of subjects who also had statistically significant superior vena cava compression at diagnosis. Primary thromboprophylaxis did not significantly affect TE occurrence; however, larger studies are warranted to consider strategic thromboprophylaxis guided by radiological monitoring of dynamic vascular compression to improve TE outcomes.

Cancer-associated thrombosis in pediatric patients

Childhood malignancy and especially acute lymphoblastic leukemia are increasingly associated with thromboembolism. The etiology of pediatric cancer associated thrombosis is multifactorial and may reflect a tumor mass effect, tumor thrombi, alterations of the hemostatic system, treatment-related hazards (e.g. procoagulant changes induced by chemotherapy), presence of central venous lines and comorbidities (e.g. inherited thrombophilia). With over 80% cure rates of childhood cancer, strategies for prevention as well as for early diagnosis and optimal treatment of thromboembolism in children with malignancies are of major importance. While the use of therapeutic low molecular weight heparin prevails, prospective studies regarding guidelines for treatment or prevention are currently lacking. This review will address the epidemiology, etiology and risk factors for thrombosis, describe the presently available evidence associated with current therapy, and offer a glimpse into future treatment options.

Thrombosis as a treatment complication in Hodgkin lymphoma patients: a comprehensive analysis of three prospective randomized German Hodgkin Study Group (GHSG) trials

BACKGROUND

The prognosis of Hodgkin lymphoma (HL) is excellent rendering research into treatment complications highly important. An important complication of cancer and its treatment is thrombosis. Thrombotic events are regularly observed in HL patients but precise information on incidence and risk factors is lacking and the value of prophylactic anticoagulation unclear.

PATIENTS AND METHODS

Thus, we comprehensively studied thrombotic events in 5773 patients from the German Hodgkin Study Group (GHSG) HD13-15 trials in early-favorable, intermediate and advanced HL. We estimated the incidence of and identified risk factors for thrombotic events. Additionally, we provide detailed data on the time course and characteristics of thrombotic events.

RESULTS

A total of 193 thrombotic events occurred for an incidence of 3.3%. Out of these, 175 (90.7%) were venous thromboses, 3 (1.5%) newly emerging post-thrombotic syndromes and 15 (7.8%) arterial thromboses. There were 11 (0.7%) events in early-favorable, 27 (1.3%) in early-unfavorable and 155 (7.3%) in advanced patients, the latter incidence being significantly higher (P < 0.001). The most common locations were deep vein thrombosis of the arm (46.3%) and leg (24.6%). Most venous thrombotic events occurred during chemotherapy (78.9%). We observed 59 (30.6%) catheter-associated events and a descriptively increased risk of venous thrombotic events in patients with oral contraception use during treatment (6.8% versus 3.9%). In advanced HL, the incidence of venous thrombotic events was increased upon treatment with BEACOPP-14 (9.4%, P = 0.0079) compared with 5.1% with 6×BEACOPPesc and 5.7% with 8×BEACOPPesc. Among commonly applied risk factors, including the Khorana score, only age and smoking were prognostic.

CONCLUSIONS

The incidence of thrombotic events in advanced stage HL is comparable to other high-risk cancer patients, especially if treated with dose-dense regimens. Additional risk factors are higher age and smoking. Selected HL patients could benefit from prophylactic anticoagulation, however, further interventional studies are needed before general recommendations can be made.

The Incidence of Venous Thromboembolism and Impact on Survival in Hodgkin Lymphoma

BACKGROUND

Thrombosis increase the acute and long-term morbidity and mortality in malignancy patients. We analyzed venous thromboembolism (VTE) in patients with Hodgkin lymphoma, the impact of VTE on survival, predisposing factors for VTE, and predicting value of Khorana and ThroLy score models.

PATIENTS AND METHODS

We included 150 adult patients with Hodgkin lymphoma between January 2010 and 2018 at our university hospital.

RESULTS

VTE was observed in 31 patients (20.7%). The types of VTE were 18 upper and 3 lower extremity deep vein thrombosis and 10 pulmonary embolism (1 with lower extremity deep vein thrombosis). Twenty-nine patients developed VTE during the treatment with a median time of episode as 5 months. In logistic regression analysis, a body mass index of >32 kg/m², high fibrinogen levels, initial thrombocytosis and leukocytosis, splenic and extranodal involvement, presence of a central venous line, advanced stage, line of treatment status of thromboprophylaxis, VTE timing, and better Eastern Cooperative Oncology Group performance scores were observed to be related with VTE. Kaplan Meier survival analysis showed a negative impact of VTE on survival. Khorana and ThroLy risk assessment models were found predictive for VTE (P = .000 and P = .003, respectively), although only ThroLy score was associated with the survival.

CONCLUSION

Thromboprophylaxis and precautions for VTE in patients with Hodgkin lymphoma according to validated risk assessment models can improve prognosis and quality of life owing to the impact of VTE on survival in the study.

The association of mediastinal mass in the formation of thrombi in pediatric patients with non-lymphoblastic lymphomas

BACKGROUND

Children diagnosed with cancer are at a significantly higher risk of developing a thrombotic event (TE) compared with the general population. The rarity of these events makes it difficult to discern the specific risk factors; however, age, sex, presence of central venous lines, inherited thrombophilia, and mediastinal mass may play a role. The primary aim of this study is to identify prognostic characteristics of children diagnosed with non-lymphoblastic lymphomas associated with a greater risk of developing a TE early on in their disease, with an increased focus on mediastinal mass characteristics.

METHODS

Retrospective chart review of pediatric patients diagnosed with non-lymphoblastic lymphoma between 2004 and 2014 at St. Jude Children's Research Hospital.

RESULTS

TE occurred in 8.5% (n = 28/330) of individuals at a median of 21 days from the diagnosis of a non-lymphoblastic lymphoma, with 60% of TEs occurring within 30 days of diagnosis. Of the variables evaluated, only presence of a peripherally inserted central catheter (odds ratio [OR]: 3.14 [95% CI: 1.24-7.98; P = 0.02]) and degree of superior vena cava (SVC) compression of > 25% increased the odds of developing a TE (OR: 2.2 [95% CI: 1.01-4.93; P = 0.048]).

CONCLUSION

Pediatric patients with non-lymphoblastic lymphoma are at increased risk of developing TEs. In contrast to previous studies, the presence of a mediastinal mass alone was not associated with a higher risk of TE, but individuals with a mediastinal mass with 25% or greater degree of SVC compression were more likely to develop a TE. This finding highlights a high-risk group of children who may benefit from prophylactic anticoagulation.

Incidence of venous thromboembolism and use of anticoagulation in hematological malignancies: Critical review of the literature

Venous Thromboembolism (VTE) frequently complicates the course of hematologic malignancies (HM) and its incidence is similar to that observed in high-risk solid tumors. Despite that, pharmacologic prophylaxis and treatment of VTE in patients with HM is challenging, mainly because a severe thrombocytopenia frequently complicates the course of treatments or may be present since diagnosis, thus increasing the risk of bleeding. Therefore, in this setting, safe and effective methods of VTE prophylaxis and treatment have not been well defined and hematologists generally refer to guidelines produced for cancer patients that give indications on anticoagulation in patients with thrombocytopenia. In this review, besides to summarize the incidence and the available data on prophylaxis and treatment of VTE in HM, we give some advices on how to use antithrombotic drugs in patients with HM according to platelets count.

Epidemiology of venous thrombosis in children with cancer

There has been an extensive body of research focusing on the epidemiology of thrombosis in adult cancer populations; however, there is significantly less knowledge about thrombosis in paediatric cancer populations. Thrombosis is diagnosed with increasing frequency in children being treated for cancer, and there is an urgent need to increase our understanding of the epidemiology of thrombosis in this population. Currently, there are no guidelines for identification of high-risk groups, prophylaxis or management of thrombotic complications in paediatric cancer patients. We reviewed the available literature regarding the epidemiology, mechanisms, risk factors, prophylaxis and outcomes of thrombosis in children with cancer and identified areas that require further research. The reported incidence of symptomatic venous thromboembolism (VTE) in children with cancer ranges between 2.1% and 16%, while the incidence of asymptomatic events is approximately 40%. Approximately 30% of VTE in this population is associated with central venous lines (CVL). The most common location of VTE is upper and lower extremity deep venous thrombosis (43 to 50% of events, respectively), while 50% of events in ALL patients occur in the central nervous system. Key characteristics that increase the risk of thrombosis include the type of cancer, age of the patient, the presence of a CVL, presence of pulmonary/intra thoracic disease, as well as the type of chemotherapy. Outcomes for paediatric cancer patients with VTE include post-thrombotic syndrome, pulmonary embolism, recurrent thromboembolism, destruction of upper venous system and death. Prospective studies aimed at enabling risk stratification of patients are required to facilitate development of paediatric specific recommendations related to thromboprophylaxis in this population.

Increasing Incidence and Recurrence Rate of Venous Thromboembolism in Paediatric Oncology Patients in One Single Centre Over 25 Years

Venous thromboembolism (VTE) is a serious complication in paediatric oncology patients. To identify the incidence, risk factors and recurrence rate of VTE in paediatric oncology patients, an observational, retrospective cohort study of all consecutive children (≤18 years) with malignancies, treated at the Emma Children's Hospital Academic Medical Centre between January 1989 and December 2013, was done. A matched case-control study in children with lymphomas was performed, to identify thrombotic risk factors. Cumulative recurrence-free survival after first VTE was estimated by the Kaplan-Meier method. Of the 2,183 children included (male: female = 1.4:1.0; median age, 6.6 years) with cancer, 78 patients developed VTE (3.6%; 95% confidence interval [CI], 2.8-4.4). The incidence increased from 0.8% (4/478, 95% CI, 0.0-1.6) between 1989 and 1993 to 10.4% (44/423, 95% CI, 7.6-13.4) between 2009 and 2013. Independent risk factors for VTE were age ≥ 12 years, acute lymphoblastic leukaemia (ALL) and lymphoma. The case-control study in lymphoma patients showed a trend for increased VTE incidence in stage IV lymphoma. Twelve (15.4%) patients developed recurrent thrombosis, 7 patients while on therapeutic or prophylactic anticoagulation. The cumulative recurrence-free survival after first VTE was 88.5, 87.1 and 80.6% after 1, 5 and 10 years, respectively. In conclusion, we demonstrated an increasing incidence of VTE in children with malignancies, with age ≥ 12 years, ALL and lymphoma as independent risk factors. The elevated recurrence rate underlines the importance of full anticoagulant therapy and might warrant prophylactic anticoagulation after first VTE during cancer treatment.

Pulmonary embolism and in situ pulmonary artery thrombosis in paediatrics

Data on paediatric pulmonary embolism (PE) are scarce. We sought to systematically review the current literature on childhood PE and conducted a search on paediatric PE via PubMed (1946–2013) and Embase (1980–2013). There was significant heterogeneity in reported data. Two patterns were noted: classic thromboembolic PE (TE-PE) and in situ pulmonary artery thrombosis (ISPAT). Mean age of presentation for TE-PE was 14.86 years, and 51% of cases were males. The commonest method for diagnosis of TE-PE was contrast CT with angiography (74% of patients). The diagnosis of TE-PE was often delayed. Although 85% of children with TE-PE had an elevated D-dimer at presentation, it was non-discriminatory for the diagnosis. In paediatric TE-PE, the prevalence of central venous catheters was 23%, immobilisation 38%, systemic infection 31% and obesity 13%, elevated Factor VIII or von Willebrand factor levels 27%, Protein C deficiency 17%, Factor V Leiden 14% and Protein S deficiency 7%. In patients with TE-PE, pharmacologic thrombolysis was used in 29%; unfractionated heparin was the most common initial anticoagulant treatment in 64% and low-molecular-weight heparins the most common follow-up treatment in 83%. Duration of anticoagulant therapy was variable and death was reported in 26% of TE-PE patients. In contrast to TE-PE, patients with ISPAT were not investigated systematically for presence of thrombophilia, had more surgical interventions as the initial management and were often treated with anti-platelet medications. This review summarises important data and identifies gaps in the knowledge of paediatric PE, which may help to design future studies.

Novel perspectives on diagnosis and clinical significance of the post-thrombotic syndrome in children

INTRODUCTION

Given the increase in venous thromboembolic events (VTE) in children, the incidence, diagnosis and management of post thrombotic syndrome (PTS) in children is of increasing interest. Current challenges facing clinicians caring for children with VTE is the limited evidence of the long-term outcomes for this cohort; specifically the significance and potential functional impairment associated with PTS.

AREAS COVERED

This paper reviews the current evidence to elucidate the risk factors for PTS in children, methods for diagnosis and management of PTS in children (aged less than 18 years). Medline, Cinahl and PsycINFO database searches were undertaken using key search terms. Priority areas in need of further research are highlighted. Expert commentary: The two paediatric PTS assessment tools currently in use have been acknowledged to overcall the incidence of mild PTS in children. A PTS tool's ability to distinguish between clinically significant PTS and mild PTS is crucial. Variation in how PTS has been reported in children across the literature suggests that the real incidence of moderate and /or clinically significant PTS in children is unknown. Furthermore, evidence is lacking about the functional impairment experienced by children with clinically significant PTS and what this means for their long-term health.

Venous thrombosis in children and adolescents with Hodgkin lymphoma in Sweden

INTRODUCTION

Pediatric patients with Hodgkin lymphoma (HL) have several risk factors for venous thromboembolism (VTE). Although these patients are occasionally treated with thromboprophylaxis, no guidelines are implemented in Sweden. Scarce data from adult patients indicate an increased risk of VTE, but pediatric data is largely missing. Given the favorable overall survival of HL, there should reasonably be more focus on preventing complications.

MATERIALS AND METHODS

We conducted a retrospective cohort study, including all patients registered in the Childhood Cancer Registry under the age of 18years diagnosed with HL between January 2005 and December 2015 in Sweden.

RESULTS

Data was retrieved from the medical records of all 163 patients (100%) at six Swedish pediatric cancer centers. The incidence of VTE was 7.7% (symptomatic VTE 3.9%). The median follow-up was 3.4years (range 0.3-10.5). Only five patients (3.1%) were treated with thromboprophylaxis. All VTE events occurred in the older age category (11-17years) and all but one (92.7%) had a mediastinal mass. While the VTE did not significantly affect the treatment of HL, it caused increased morbidity and 2/12 developed a post-thrombotic syndrome. No significant risk factors for VTE were identified.

CONCLUSIONS

VTE is a relatively common complication of HL and its treatment, causing increased acute and long-term morbidity. However, due to limited number of events we could not demonstrate risk-factors for VTE that would identify patients who might benefit from thromboprophylaxis.

Post thrombotic syndrome following deep vein thrombosis in paediatric patients

Background Although well characterised in adults, less is known about post-thrombotic syndrome in children. In this review, current knowledge regarding paediatric post-thrombotic syndrome is summarised, with particular emphasis on pathophysiology, aetiology, diagnosis and management. Methods A Medline literature review was performed using search terms 'post thrombotic syndrome', 'post phlebitic syndrome', paediatric and children. Relevant articles were identified and included for summation analysis. Results The incident of paediatric venous thromboembolism is rising. Deep vein thrombosis can cause venous hypertension through a combination of venous reflux, venous obstruction and impairment of the calf muscle pump, leading to development of post-thrombotic syndrome. In children, this is more likely to occur if deep vein thrombosis diagnosis and treatment are delayed, if a higher number of vessels are involved, and if factors such as D-dimer are elevated at diagnosis and throughout treatment. Post-thrombotic syndrome occurs in about 26% of paediatric deep vein thrombosis, though the results of individual studies vary widely. A number of tools exist to diagnose paediatric post-thrombotic syndrome, including the modified Villalta scale and Manco-Johnson instrument. Once post-thrombotic syndrome develops, the mainstay of treatment remains supportive, with little evidence of benefit from pharmacological measures. Conclusion Surgical or interventional treatment is not advised except in exceptional cirumstances, due to variable prognosis of PTS in paediatric populations with rising incidence of paediatric venous thromboembolism, it follows that the prevalence of post-thrombotic syndrome in children may also increase. Evidence-based venous thromboembolism prevention strategies need to be implemented for prevention of deep vein thrombosis, but when it does occur, deep vein thrombosis requires prompt and effective treatment to prevent post-thrombotic syndrome. Optimum treatment strategies for post-thrombotic syndrome require further investigation.

Venous Thromboembolism in Children with Cancer and Blood Disorders

Venous thromboembolism (VTE) in children is multifactorial and most often related to a combination of inherited and acquired thrombophilias. Children with cancer and blood disorders are often at risk for VTE due to disease-related factors such as inflammation and abnormal blood flow and treatment-related factors such as central venous catheters and surgery. We will review risk factors for VTE in children with leukemia, lymphoma, and solid tumors. We will also review risk factors for VTE in children with blood disorders with specific focus on sickle cell anemia and hemophilia. We will present the available evidence and clinical guidelines for prevention and treatment of VTE in these populations.

[Superior vena cava thrombosis in patients with mediastinal large B-cell lymphoma: two pediatric cases]

We report two pediatric cases of superior vena cava thrombosis (VTE) in patients treated for primary mediastinal large B-cell lymphoma (PMBCL). PMBCL is a rare entity in children and adolescents and no thrombosis has been described in this population. Thrombosis in lymphoma is frequently asymptomatic, detected as an incidental finding in the first months following diagnosis. The thrombosis mechanisms are often multifactorial based on veinous compression by the mass, elevated risk of thrombosis in neoplasia, and/or presence of a central catheter. The risk factors of venous thromboembolism (VTE) in lymphoma are high-grade lymphoma, comorbidities, central nervous system lymphoma, and mediastinal mass. Because thrombosis has an impact on prognosis and treatment, it seems important to improve knowledge in order to improve the diagnosis and prevention of thrombosis in lymphoma.

Thrombosis and hemostatic abnormalities in hematological malignancies

There is a paucity of data that pertain to thrombosis in patients with hematological malignancies. Recent studies showed that patients with lymphoma, multiple myeloma, and acute leukemia have an increased thrombotic risk, particularly at the time of diagnosis and during chemotherapy. We searched the PubMed database for articles on thromboembolic complications in patients with hematological malignancies published between 1996 and 2013. The incidence of thrombotic events is variable, and is influenced by the type and the stage of hematological malignancy, the antitumor therapy, and the use of central venous devices. The pathogenesis of thromboembolic disease in hematological malignancies is multifactorial. Tumor cell-derived procoagulant, fibrinolytic, or proteolytic factors, and inflammatory cytokines affect clotting activation, and chemotherapy and immunomodulatory drugs increase the thrombotic risk in patients with lymphoma, acute leukemia, and multiple myeloma. Infections might also contribute to the pathogenesis of the thromboembolic complications: endotoxins from gram-negative bacteria induce the release of tissue factor, tumor necrosis factor and interleukin-1b, and gram-positive organisms can release bacterial mucopolysaccharides that directly activate factor XII. In the setting of plasma cell dyscrasias, hyperviscosity, decreased fibrinolysis, procoagulant autoantibody production, inflammatory cytokines, acquired activated protein C resistance, and the prothrombotic effects of antimyeloma agents might be the cause of thromboembolic complications. Anticoagulant therapy is very complicated because of high risk of hemorrhage. Therefore, an accurate estimate of a patient's thrombotic risk is essential to allow physicians to target thromboprophylaxis in high-risk patients.

Venous thromboembolism in children with cancer - a population-based cohort study

Introduction

Cancer is a known risk factor for venous thromboembolism (VTE) in adults, but population-based data in children are scarce.

Materials and methods

We conducted a cohort study utilising linkage of the Clinical Practice Research Database (primary care), Hospital Episodes Statistics (secondary care), UK Cancer Registry data and Office for National Statistics cause of death data. From these databases, we selected 498 children with cancer diagnosed between 1997 and 2006 and 20,810 controls without cancer. We calculated VTE incidence rates in children with cancer vs. controls, and hazard ratios (HRs) using Cox regression.

Results

We identified four VTE events in children with cancer compared with four events in the larger control population corresponding to absolute risks of 1.52 and 0.06 per 1000 person-years respectively. The four children with VTE and cancer were diagnosed with hematological, bone or non-specified cancer. Childhood cancer was hence associated with a highly increased risk of VTE (HR adjusted for age and sex: 28.3; 95%CI = 7.0-114.5).

Conclusions

Children with cancer are at increased relative risk of VTE compared to those without cancer. Physicians could consider thromboprophylaxis in children with cancer to reduce their excess risk of VTE however the absolute risk is extremely small and the benefit gained therefore would need to be balanced against the risk invoked of implementing such a strategy.

Novelty & Impact Statements

While there is a reasonable level of knowledge about the risk of VTE in adult populations, it is not well known whether this risk is reflected in paediatric patients. We found a substantial increase in risk of VTE in children with cancer compared to a child population without cancer. While this finding is important, the absolute risk of VTE is still low and must be balanced with the risks of anticoagulation.

Body mass index and thromboembolism in children with hematological malignancies

We evaluated the effects of body mass index (BMI) on the risk of thromboembolism (TE) in children (<18 years) with hematological malignancies during the period 1990-2009 (n = 359). Obesity was prevalent in 12% of patients: 6% versus 17% prior to and after the year 2000 (P = 0.02). Sixty-one (17%) patients developed TE; increasing BMI was associated with increased, but statistically insignificant risk of TE [adjusted odds ratios (OR): 0.75 (95%CI 0.32-1.77), 0.93 (95%CI 0.38-2.30), and 1.01(95%CI 0.42-2.41) for underweight, overweight, and obese group]. A large prospective study is needed to define the impact of BMI on the risk of TE in children.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

Central venous line dysfunction is an independent predictor of poor survival in children with cancer

Central venous line (CVL) dysfunction (mainly from thrombotic occlusion) is a frequent, but relatively less-studied complication compared with infection and thromboembolism (TE). In adults with cancer, TE results in poor outcome. We evaluated the impact of CVL-dysfunction and TE on overall survival (OS) and event-free survival (EFS) in children with noncentral nervous system cancer (n=358). CVL-dysfunction was defined as persistent or recurrent difficulty of blood draw and/or infusion. Event was defined as cancer relapse, second malignancy, or death due to any cause. OS and EFS were estimated using Kaplan-Meier method and survival curves compared using log-rank test. Hazard ratios (HR) were calculated using the Weibull regression model. Diagnosis of TE (n=43, 12%) had no effect on the OS and EFS. Children with CVL-dysfunction (n=74, 21%) had shorter 5- and 10-year EFS compared with children without CVL-dysfunction (P=0.029 and P=0.027). Multiple regression analyses, adjusting for age, sex, diagnostic era, TE, and cancer type identified CVL-dysfunction as an independent determinant of 5-year OS (HR 1.87; 95% confidence interval, 1.02-3.42; P=0.043) and EFS (HR 1.96; 95% confidence interval, 1.23-3.41; P=0.018). Although the etiology of adverse impact of CVL-dysfunction on survival is unknown, its prevention and prompt treatment may improve outcome from cancer in children. Further prospective studies are recommended.

Venous thrombosis in children: an emerging issue

More and more cases of venous thrombosis are diagnosed in children thanks to newer imaging modalities. Central venous catheters have become commonplace in the care of critically ill children and have contributed to the increased rate of thrombotic events. Lastly, children who develop life-threatening or chronic medical conditions are surviving longer because of advanced medical therapies; these intensive therapies can be complicated by events such as thrombosis. Over the last 10 years, specific guidelines for treating thrombosis in children have become available. Nevertheless, in many situations anticoagulant treatment is specially tailored to each individual patient's needs. Some new antithrombotic drugs which have undergone clinical testing in adults might be beneficial to paediatric patients with thromboembolic disorders; unfortunately, clinical data and reports on the use of these drugs in children, when available, are extremely limited. The aim of this review is to provide physicians with enough background information to be able to manage thrombosis in children. First, by helping them detect a thrombotic event in a child. Upon confirmation of the diagnosis, the physician will request the appropriate tests and will choose the best treatment on the basis of the guidelines and recommendations. Moreover, the paediatrician will have the information he or she needs to identify which children are at highest risk of acute thrombotic events and relevant long-term sequelae and, therefore, to decide on the appropriate prophylactic or pharmacologic strategy. Lastly, we would like to provide the paediatrician with information on future drugs with regard to the treatment and prophylaxis of thrombosis.

Post-thrombotic syndrome in children: a systematic review of frequency of occurrence, validity of outcome measures, and prognostic factors

BACKGROUND

Post-thrombotic syndrome is a manifestation of chronic venous insufficiency following deep venous thrombosis. This systematic review was conducted to critically evaluate pediatric evidence on frequency of occurrence, validity of outcome measures, and prognostic indicators of post-thrombotic syndrome.

DESIGN AND METHODS

A comprehensive literature search of original reports revealed 19 eligible studies, totaling 977 patients with upper/lower extremity deep venous thrombosis. Calculated weighted mean frequency of post-thrombotic syndrome was 26% (95% confidence interval: 23-28%) overall, and differed significantly by prospective/non-prospective analysis and use/non-use of a standardized outcome measure.

RESULTS

Standardized post-thrombotic syndrome outcome measures included an adaptation of the Villalta scale, the Clinical-Etiologic-Anatomic-Pathologic classification, and the Manco-Johnson instrument. Data on validity were reported only for the Manco-Johnson instrument. No publications on post-thrombotic syndrome-related quality of life outcomes were identified. Candidate prognostic factors for post-thrombotic syndrome in prospective studies included use/non-use of thrombolysis and plasma levels of factor VIII activity and D-dimer.

CONCLUSIONS

Given that affected children must endure chronic sequelae for many decades, it is imperative that future collaborative pediatric prospective cohort studies and trials assess as key objectives and outcomes the incidence, severity, prognostic indicators, and health impact of post-thrombotic syndrome, using validated measures.

Venous thromboembolism in the hematologic malignancies

Patients with hematologic malignancies are at high risk of thrombotic or hemorrhagic complications. The incidence of these events is greatly variable and is influenced by many factors, including the type of disease, the type of chemotherapy, and the use of a central venous device. As in solid tumors, a number of clinical risk factors have been identified and contribute to the increasing thrombotic rate in hematologic malignancies. Biologic properties of the tumor cells can influence the hypercoagulable state of patients with these malignancies by several mechanisms. Of interest, oncogenes responsible for neoplastic transformation in leukemia also may be involved in clotting activation. Epidemiologic data allow an estimate of the incidence of venous thromboembolism (VTE) in acute leukemia, lymphomas, and multiple myeloma (MM). In this review, we focus on the epidemiology, pathogenesis, and VTE management in these three hematologic malignancies. No recommendation for routine thromboprophylaxis in these conditions, with the exception of MM, is available. Large, prospective, randomized clinical trials are needed to establish the best practice for thromboprophylaxis and treatment of VTE in these types of cancers.

Treatment of venous thromboembolism in patients with cancer: Guidelines of the Italian Society for Haemostasis and Thrombosis (SISET)

BACKGROUND

The treatment of venous thromboembolism (VTE) in cancer patients remains controversial.

PURPOSE

The Italian Society for Thrombosis and Haemostasis (SISET) commissioned a project to develop clinical practice guidelines for the therapy of VTE in patients with malignancies.

METHODS

Key questions about the treatment of VTE in patients with malignancies were formulated by a multidisciplinary working group consisting of experts in clinical medicine and research. After a systematic review and discussion of the literature, recommendations were formulated and graded according to the supporting evidence. For those questions for which the literature search did not yield any definitive answer (absence of evidence evidence of low quality, and contradictory evidence), a formal consensus method was used to issue clinical recommendations.

RESULTS

The results of the available literature on VTE treatment in cancer patients were reviewed and clinical recommendations were drafted.

CONCLUSION

We describe the results of a systematic literature review and an explicit approach to consensus techniques which resulted in recommendations for the key therapeutic issues in cancer patients with VTE.

Epidemiology and clinical risk factors predisposing to thromboembolism in children with cancer

PURPOSE

The prevalence and risk factors for thromboembolism (TE) in children with cancer are largely unknown. This retrospective cohort study aims to determine the epidemiology of TE and to identify potential risk factors for TE in children with cancer.

METHODS

We used logistic regression to determine the association of age (<10 years vs. > or =10 years), gender, type of cancer, presence or absence of intra-thoracic disease (mediastinal mass or any primary or metastatic pulmonary disease), type of central venous line (CVL) and CVL-dysfunction (difficulty of blood draw, infusion or documented CVL infection) on the risk of developing TE.

RESULTS

Fifty-seven of 726 patients [7.9%; 95% confidence intervals (CI); 6.0,10.0] developed TE; children with brain tumors (n = 201) had significantly lower prevalence of TE (0.5%; P < 0.001). Older patients had increased risk of developing TE compared to younger patients [Odds ratios (OR) 1.8; 95% CI; 1.0,3.2; P = 0.036]. Children with acute lymphoblastic leukemia (ALL) (OR 4.6; 95% CI; 1.8, 12.3; P = 0.002), lymphoma (OR 3.8; 95% CI; 1.3, 11.1; P = 0.016), and sarcoma (OR 4.3; 95% CI; 1.4, 13.3; P = 0.012) had an increased risk of TE. Subgroup analyses showed that patients with CVL-dysfunction and intra-thoracic disease had a higher prevalence of TE compared to those without CVL-dysfunction (22.8% vs. 8.8%; 95% CI; 4.0, 24.3; P = 0.006) and intra-thoracic disease (18.0% vs. 6.1%; 95% CI; 2.4, 21.4; P = 0.02).

CONCLUSIONS

TE is common in children with cancer. Age and type of cancer are independent risk factors for TE in children with non-CNS cancers. CVL-dysfunction and intra-thoracic disease are significantly associated with the diagnosis of TE.