Thrombosis in pediatric malignancy: a review and future perspectives with focus on management

The Evaluation of Central Venous Catheter-related Complications in Pediatric Acute Leukemia Patients: Single Center Experience

Central venous catheters (CVCs) are important for maintenance of childhood leukemia treatment but CVCs may develop complications. The aim of this study was to retrospectively evaluate the CVC-related complication rate, complication types, and outcome in children with acute leukemia. Complications developing in 310 CVCs (ports n=250, Hickman catheters n=60) inserted in 262 patients were evaluated. A total of 225,296 catheter days were screened. Median (range) CVC in-dwelling time was 661.5 (1 to 2636) days. In total, 157 complications developed of which 91 (58%) were infectious complications, 35 (22.3%) were vascular, 19 (12.1%) were surgical, and 12 (7.6%) were mechanical. Hickman catheters had a higher complication rate and were more prone to mechanical complications ( P <0.01) but there was no difference for other complications. A lower absolute neutrophil count at insertion was observed in children with infectious complications ( P <0.01). Seventy-eight of 136 catheters (57.3%) had to be removed prematurely. The overall complication rate was 0.65 per 1000 catheter days. In multivariate analysis, relapse leukemia, Hickman catheter and low absolute neutrophil count increased complication risk by 4.00, 1.97, and 1.92 times, respectively. Five (1.9%) deaths occurred because of catheter complications. Safe use of CVCs can be improved by early detection of complications and an experienced catheter care team.

Thrombosis and Anticoagulant Therapy Among Pediatric Cancer Patients: Real-Life Data

Background: Venous thromboembolism (VTE) in children is relatively rare, and more so among those with cancer. In this study, we report the characteristics and outcomes of children with cancer-associated thrombosis.

Methods: We reviewed institutional databases for all children with cancer and a diagnosis of VTE at King Hussein Cancer Center in Jordan. Variables reviewed are patients’ clinical characteristics, treatment for cancer, and anticoagulation therapy.

Results: Between January 2011 and December 2018, a total of 45 patients fulfilled the inclusion criteria, and the median age was 10.4 (0.8-17.9) years. The most common underlying diagnosis was acute lymphoblastic leukemia (n = 13, 29%). At the time of VTE, 29 (64.4%) patients were receiving chemotherapy, and eight (17.8%) had a central venous catheter (CVC). The majority of patients (n = 37, 82%) developed VTE within 30 days of hospitalization. Thrombosis mostly involved the extremities (n = 23, 51%) and sagittal vein (n = 12, 26.7%). All patients were treated with low-molecular-weight heparin (LMWH), complicated by bleeding in three (6.6%) patients.

Conclusion: In contrast to adults, VTE in pediatric cancer patients is more associated with chemotherapy and recent hospitalization. LMWH is a safe and effective therapy for children with cancer who develop VTE.

Venous Thromboembolism in Pediatric Cancer Patients with Central Venous Catheter-A Systematic Review and Meta-analysis

Pediatric cancer patients hold an increased risk of venous thromboembolism (VTE) due to their cancer. Central venous catheters (CVCs) further increase the VTE risk. This systematic literature review elucidates the VTE incidence in pediatric cancer patients with CVC. MEDLINE and EMBASE were searched in August 2020 without time limits. We included studies reporting original data on patients ≤18 years with any CVC type and any cancer type, who were examined for VTE with ≥7 days follow-up. In total, 682 unique records were identified, whereof 189 studies were assessed in full text. Altogether, 25 studies were included, containing 2,318 pediatric cancer patients with CVC, of which 17% suffered VTE. Fifteen studies (n = 1,551) described CVC-related VTE and reported 11% CVC-related VTE. Concerning cancer type, 991 children suffered from acute lymphoblastic leukemia (ALL) and 616 from solid tumors. Meta-analysis revealed VTE incidence (95% confidence interval) of 21% (8-37) for ALL and 7% (0.1-17) for solid tumors. Additionally, 20% of children with tunneled or nontunneled CVC and 12% of children with implantable ports suffered VTE. In conclusion, pediatric cancer patients with CVC have substantial VTE risk. Children with ALL and CVC have higher VTE incidence than children with solid tumors and CVC. Implantable port catheter should be preferred over tunneled or nontunneled CVC to reduce VTE risk. Thrombophilia investigation does not seem relevant in pediatric cancer patients with CVC and VTE. To prevent VTE, intensified catheter care is recommended, especially in children with ALL.

Assessment of provider practices regarding venous thromboembolism management and prevention in pediatric acute leukemia patients

Despite the known occurrence of venous thromboembolism (VTE) in the pediatric oncology population, there are no leukemia-specific VTE treatment guidelines. The primary objective of this study was to assess current practices regarding the management and prevention of VTE in the pediatric acute lymphoblastic leukemia (ALL) population. We performed a cross sectional, anonymous, electronic survey of members of the American Society of Hematology and the pediatric subcommittee of VENUS (VTE Network US of the Hemostasis and Thrombosis Research Society). Survey items included questions on demographics and clinical practice. Of 870 surveys distributed, 154 were submitted, giving a 17.7% response rate. Treatment duration, re-imaging timeline, and class of anticoagulants used were reported for catheter-associated deep vein thrombus, pulmonary embolism, and cerebral venous sinus thrombosis. While there are some common themes regarding VTE management, there is notable variation in the overall practice as well as with the decision to continue anticoagulation in the presence of thrombocytopenia. Given the variation seen, a multi-center, prospective clinical trial is urgently needed for developing consensus guidelines for the management of VTE in children with ALL.

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.